Use Instant instead of milliseconds for filesystem timestamp handling

This enables higher file timestamp resolution on filesystems like ext4,
Mac APFS (1ns) or NTFS (100ns) providing high timestamp resolution on
filesystem level.

Note:
- on some OSes Java 8,9 truncate milliseconds, see
https://bugs.openjdk.java.net/browse/JDK-8177809, fixed in Java 10
- UnixFileAttributes truncates timestamp resolution to microseconds when
converting the internal representation to FileTime exposed in the API,
see https://bugs.openjdk.java.net/browse/JDK-8181493
- WindowsFileAttributes also provides only microsecond resolution

Change-Id: I25ffff31a3c6f725fc345d4ddc2f26da3b88f6f2
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit.http.server/src/org/eclipse/jgit/http/server/FileSender.java

@@ -58,12 +58,14 @@
 import java.io.OutputStream;
 import java.io.RandomAccessFile;
 import java.text.MessageFormat;
+import java.time.Instant;
 import java.util.Enumeration;
 
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
 import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.util.FS;
 
 /**
  * Dumps a file over HTTP GET (or its information via HEAD).
@@ -76,7 +78,7 @@ final class FileSender {
 
 	private final RandomAccessFile source;
 
-	private final long lastModified;
+	private final Instant lastModified;
 
 	private final long fileLen;
 
@@ -89,7 +91,7 @@ final class FileSender {
 		this.source = new RandomAccessFile(path, "r");
 
 		try {
-			this.lastModified = path.lastModified();
+			this.lastModified = FS.DETECTED.lastModifiedInstant(path);
 			this.fileLen = source.getChannel().size();
 			this.end = fileLen;
 		} catch (IOException e) {
@@ -114,7 +116,7 @@ void close() {
 		}
 	}
 
-	long getLastModified() {
+	Instant getLastModified() {
 		return lastModified;
 	}
 

org.eclipse.jgit.http.server/src/org/eclipse/jgit/http/server/ObjectFileServlet.java

@@ -54,6 +54,7 @@
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.time.Instant;
 
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServlet;
@@ -76,7 +77,9 @@ static class Loose extends ObjectFileServlet {
 
 		@Override
 		String etag(FileSender sender) throws IOException {
-			return Long.toHexString(sender.getLastModified());
+			Instant lastModified = sender.getLastModified();
+			return Long.toHexString(lastModified.getEpochSecond())
+					+ Long.toHexString(lastModified.getNano());
 		}
 	}
 
@@ -145,7 +148,9 @@ private void serve(final HttpServletRequest req,
 
 		try {
 			final String etag = etag(sender);
-			final long lastModified = (sender.getLastModified() / 1000) * 1000;
+			// HTTP header Last-Modified header has a resolution of 1 sec, see
+			// https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.29
+			final long lastModified = sender.getLastModified().getEpochSecond();
 
 			String ifNoneMatch = req.getHeader(HDR_IF_NONE_MATCH);
 			if (etag != null && etag.equals(ifNoneMatch)) {

org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/LocalDiskRepositoryTestCase.java

@@ -51,6 +51,7 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
@@ -322,12 +323,13 @@ public static String indexState(Repository repo, int includedOptions)
 			throws IllegalStateException, IOException {
 		DirCache dc = repo.readDirCache();
 		StringBuilder sb = new StringBuilder();
-		TreeSet<Long> timeStamps = new TreeSet<>();
+		TreeSet<Instant> timeStamps = new TreeSet<>();
 
 		// iterate once over the dircache just to collect all time stamps
 		if (0 != (includedOptions & MOD_TIME)) {
-			for (int i=0; i<dc.getEntryCount(); ++i)
+			for (int i = 0; i < dc.getEntryCount(); ++i) {
-				timeStamps.add(Long.valueOf(dc.getEntry(i).getLastModified()));
+				timeStamps.add(dc.getEntry(i).getLastModifiedInstant());
+			}
 		}
 
 		// iterate again, now produce the result string
@@ -339,7 +341,8 @@ public static String indexState(Repository repo, int includedOptions)
 				sb.append(", stage:" + stage);
 			if (0 != (includedOptions & MOD_TIME)) {
 				sb.append(", time:t"+
-						timeStamps.headSet(Long.valueOf(entry.getLastModified())).size());
+						timeStamps.headSet(entry.getLastModifiedInstant())
+								.size());
 			}
 			if (0 != (includedOptions & SMUDGE))
 				if (entry.isSmudged())

org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/RepositoryTestCase.java

@@ -57,7 +57,9 @@
 import java.io.InputStreamReader;
 import java.io.Reader;
 import java.nio.file.Path;
+import java.time.Instant;
 import java.util.Map;
+import java.util.concurrent.TimeUnit;
 
 import org.eclipse.jgit.api.Git;
 import org.eclipse.jgit.api.errors.GitAPIException;
@@ -284,7 +286,7 @@ protected void resetIndex(FileTreeIterator treeItr)
 
 				dce = new DirCacheEntry(treeItr.getEntryPathString());
 				dce.setFileMode(treeItr.getEntryFileMode());
-				dce.setLastModified(treeItr.getEntryLastModified());
+				dce.setLastModified(treeItr.getEntryLastModifiedInstant());
 				dce.setLength((int) len);
 				try (FileInputStream in = new FileInputStream(
 						treeItr.getEntryFile())) {
@@ -361,7 +363,8 @@ public static String slashify(String str) {
 	 * @throws InterruptedException
 	 * @throws IOException
 	 */
-	public static long fsTick(File lastFile) throws InterruptedException,
+	public static Instant fsTick(File lastFile)
+			throws InterruptedException,
 			IOException {
 		File tmp;
 		FS fs = FS.DETECTED;
@@ -375,15 +378,15 @@ public static long fsTick(File lastFile) throws InterruptedException,
 			tmp = File.createTempFile("fsTickTmpFile", null,
 					lastFile.getParentFile());
 		}
-		long res = FS.getFsTimerResolution(tmp.toPath()).toMillis();
+		long res = FS.getFsTimerResolution(tmp.toPath()).toNanos();
 		long sleepTime = res / 10;
 		try {
-			long startTime = fs.lastModified(lastFile);
+			Instant startTime = fs.lastModifiedInstant(lastFile);
-			long actTime = fs.lastModified(tmp);
+			Instant actTime = fs.lastModifiedInstant(tmp);
-			while (actTime <= startTime) {
+			while (actTime.compareTo(startTime) <= 0) {
-				Thread.sleep(sleepTime);
+				TimeUnit.NANOSECONDS.sleep(sleepTime);
 				FileUtils.touch(tmp.toPath());
-				actTime = fs.lastModified(tmp);
+				actTime = fs.lastModifiedInstant(tmp);
 			}
 			return actTime;
 		} finally {

org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/time/TimeUtil.java

@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2019, Matthias Sohn <matthias.sohn@sap.com>
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package org.eclipse.jgit.junit.time;
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.attribute.FileTime;
+import java.time.Instant;
+
+import org.eclipse.jgit.util.FS;
+
+/**
+ * Utility methods for handling timestamps
+ */
+public class TimeUtil {
+	/**
+	 * Set the lastModified time of a given file by adding a given offset to the
+	 * current lastModified time
+	 *
+	 * @param path
+	 *            path of a file to set last modified
+	 * @param offsetMillis
+	 *            offset in milliseconds, if negative the new lastModified time
+	 *            is offset before the original lastModified time, otherwise
+	 *            after the original time
+	 * @return the new lastModified time
+	 */
+	public static Instant setLastModifiedWithOffset(Path path,
+			long offsetMillis) {
+		Instant mTime = FS.DETECTED.lastModifiedInstant(path)
+				.plusMillis(offsetMillis);
+		try {
+			Files.setLastModifiedTime(path, FileTime.from(mTime));
+			return mTime;
+		} catch (IOException e) {
+			throw new UncheckedIOException(e);
+		}
+	}
+
+	/**
+	 * Set the lastModified time of file a to the one from file b
+	 *
+	 * @param a
+	 *            file to set lastModified time
+	 * @param b
+	 *            file to read lastModified time from
+	 */
+	public static void setLastModifiedOf(Path a, Path b) {
+		Instant mTime = FS.DETECTED.lastModifiedInstant(b);
+		try {
+			Files.setLastModifiedTime(a, FileTime.from(mTime));
+		} catch (IOException e) {
+			throw new UncheckedIOException(e);
+		}
+	}
+
+}

org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/ShowDirCache.java

@@ -48,8 +48,10 @@
 
 import static java.lang.Integer.valueOf;
 
-import java.text.SimpleDateFormat;
+import java.time.Instant;
-import java.util.Date;
+import java.time.ZoneId;
+import java.time.format.DateTimeFormatter;
+import java.util.Locale;
 
 import org.eclipse.jgit.dircache.DirCache;
 import org.eclipse.jgit.dircache.DirCacheEntry;
@@ -67,25 +69,27 @@ class ShowDirCache extends TextBuiltin {
 	/** {@inheritDoc} */
 	@Override
 	protected void run() throws Exception {
-		final SimpleDateFormat fmt;
+		final DateTimeFormatter fmt = DateTimeFormatter
-		fmt = new SimpleDateFormat("yyyy-MM-dd,HH:mm:ss.SSS"); //$NON-NLS-1$
+				.ofPattern("yyyy-MM-dd,HH:mm:ss.nnnnnnnnn") //$NON-NLS-1$
+				.withLocale(Locale.getDefault())
+				.withZone(ZoneId.systemDefault());
 
 		final DirCache cache = db.readDirCache();
 		for (int i = 0; i < cache.getEntryCount(); i++) {
 			final DirCacheEntry ent = cache.getEntry(i);
 			final FileMode mode = FileMode.fromBits(ent.getRawMode());
 			final int len = ent.getLength();
-			long lastModified = ent.getLastModified();
+			Instant mtime = ent.getLastModifiedInstant();
-			final Date mtime = new Date(lastModified);
 			final int stage = ent.getStage();
 
 			outw.print(mode);
 			outw.format(" %6d", valueOf(len)); //$NON-NLS-1$
 			outw.print(' ');
-			if (millis)
+			if (millis) {
-				outw.print(lastModified);
+				outw.print(mtime.toEpochMilli());
-			else
+			} else {
 				outw.print(fmt.format(mtime));
+			}
 			outw.print(' ');
 			outw.print(ent.getObjectId().name());
 			outw.print(' ');

org.eclipse.jgit.test/META-INF/MANIFEST.MF

@@ -40,6 +40,7 @@ Import-Package: com.googlecode.javaewah;version="[1.1.6,2.0.0)",
  org.eclipse.jgit.internal.storage.reftable;version="[5.1.9,5.2.0)",
  org.eclipse.jgit.internal.storage.reftree;version="[5.1.9,5.2.0)",
  org.eclipse.jgit.junit;version="[5.1.9,5.2.0)",
+ org.eclipse.jgit.junit.time;version="[5.1.9,5.2.0)",
  org.eclipse.jgit.lfs;version="[5.1.9,5.2.0)",
  org.eclipse.jgit.lib;version="[5.1.9,5.2.0)",
  org.eclipse.jgit.merge;version="[5.1.9,5.2.0)",
@@ -62,12 +63,12 @@ Import-Package: com.googlecode.javaewah;version="[1.1.6,2.0.0)",
  org.eclipse.jgit.util;version="[5.1.9,5.2.0)",
  org.eclipse.jgit.util.io;version="[5.1.9,5.2.0)",
  org.eclipse.jgit.util.sha1;version="[5.1.9,5.2.0)",
- org.tukaani.xz;version="[1.6.0,2.0)",
  org.junit;version="[4.12,5.0.0)",
  org.junit.experimental.theories;version="[4.12,5.0.0)",
  org.junit.rules;version="[4.12,5.0.0)",
  org.junit.runner;version="[4.12,5.0.0)",
  org.junit.runners;version="[4.12,5.0.0)",
- org.slf4j;version="[1.7.0,2.0.0)"
+ org.slf4j;version="[1.7.0,2.0.0)",
+ org.tukaani.xz;version="[1.6.0,2.0)"
 Require-Bundle: org.hamcrest.core;bundle-version="[1.1.0,2.0.0)",
  org.hamcrest.library;bundle-version="[1.1.0,2.0.0)"

org.eclipse.jgit.test/tst/org/eclipse/jgit/api/AddCommandTest.java

@@ -1266,7 +1266,7 @@ private static DirCacheEntry addEntryToBuilder(String path, File file,
 		DirCacheEntry entry = new DirCacheEntry(path, stage);
 		entry.setObjectId(id);
 		entry.setFileMode(FileMode.REGULAR_FILE);
-		entry.setLastModified(file.lastModified());
+		entry.setLastModified(FS.DETECTED.lastModifiedInstant(file));
 		entry.setLength((int) file.length());
 
 		builder.add(entry);

org.eclipse.jgit.test/tst/org/eclipse/jgit/api/CheckoutCommandTest.java

@@ -43,6 +43,7 @@
  */
 package org.eclipse.jgit.api;
 
+import static java.time.Instant.EPOCH;
 import static org.eclipse.jgit.lib.Constants.MASTER;
 import static org.eclipse.jgit.lib.Constants.R_HEADS;
 import static org.hamcrest.CoreMatchers.is;
@@ -60,6 +61,9 @@
 import java.io.IOException;
 import java.net.MalformedURLException;
 import java.net.URISyntaxException;
+import java.nio.file.Files;
+import java.nio.file.attribute.FileTime;
+import java.time.Instant;
 
 import org.eclipse.jgit.api.CheckoutResult.Status;
 import org.eclipse.jgit.api.CreateBranchCommand.SetupUpstreamMode;
@@ -74,6 +78,7 @@
 import org.eclipse.jgit.dircache.DirCacheEntry;
 import org.eclipse.jgit.junit.JGitTestUtil;
 import org.eclipse.jgit.junit.RepositoryTestCase;
+import org.eclipse.jgit.junit.time.TimeUtil;
 import org.eclipse.jgit.lfs.BuiltinLFS;
 import org.eclipse.jgit.lib.ConfigConstants;
 import org.eclipse.jgit.lib.Constants;
@@ -86,6 +91,7 @@
 import org.eclipse.jgit.storage.file.FileBasedConfig;
 import org.eclipse.jgit.transport.RemoteConfig;
 import org.eclipse.jgit.transport.URIish;
+import org.eclipse.jgit.util.FS;
 import org.eclipse.jgit.util.FileUtils;
 import org.eclipse.jgit.util.SystemReader;
 import org.junit.Before;
@@ -360,14 +366,14 @@ public void testUpdateSmudgedEntries() throws Exception {
 
 		File file = new File(db.getWorkTree(), "Test.txt");
 		long size = file.length();
-		long mTime = file.lastModified() - 5000L;
+		Instant mTime = TimeUtil.setLastModifiedWithOffset(file.toPath(),
-		assertTrue(file.setLastModified(mTime));
+				-5000L);
 
 		DirCache cache = DirCache.lock(db.getIndexFile(), db.getFS());
 		DirCacheEntry entry = cache.getEntry("Test.txt");
 		assertNotNull(entry);
 		entry.setLength(0);
-		entry.setLastModified(0);
+		entry.setLastModified(EPOCH);
 		cache.write();
 		assertTrue(cache.commit());
 
@@ -375,10 +381,12 @@ public void testUpdateSmudgedEntries() throws Exception {
 		entry = cache.getEntry("Test.txt");
 		assertNotNull(entry);
 		assertEquals(0, entry.getLength());
-		assertEquals(0, entry.getLastModified());
+		assertEquals(EPOCH, entry.getLastModifiedInstant());
 
-		db.getIndexFile().setLastModified(
+		Files.setLastModifiedTime(db.getIndexFile().toPath(),
-				db.getIndexFile().lastModified() - 5000);
+				FileTime.from(FS.DETECTED
+						.lastModifiedInstant(db.getIndexFile())
+						.minusMillis(5000L)));
 
 		assertNotNull(git.checkout().setName("test").call());
 
@@ -386,7 +394,7 @@ public void testUpdateSmudgedEntries() throws Exception {
 		entry = cache.getEntry("Test.txt");
 		assertNotNull(entry);
 		assertEquals(size, entry.getLength());
-		assertEquals(mTime, entry.getLastModified());
+		assertEquals(mTime, entry.getLastModifiedInstant());
 	}
 
 	@Test

org.eclipse.jgit.test/tst/org/eclipse/jgit/api/CommitCommandTest.java

@@ -61,6 +61,7 @@
 import org.eclipse.jgit.dircache.DirCacheBuilder;
 import org.eclipse.jgit.dircache.DirCacheEntry;
 import org.eclipse.jgit.junit.RepositoryTestCase;
+import org.eclipse.jgit.junit.time.TimeUtil;
 import org.eclipse.jgit.lib.ConfigConstants;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.FileMode;
@@ -311,11 +312,11 @@ public void commitSubmoduleUpdate() throws Exception {
 	public void commitUpdatesSmudgedEntries() throws Exception {
 		try (Git git = new Git(db)) {
 			File file1 = writeTrashFile("file1.txt", "content1");
-			assertTrue(file1.setLastModified(file1.lastModified() - 5000));
+			TimeUtil.setLastModifiedWithOffset(file1.toPath(), -5000L);
 			File file2 = writeTrashFile("file2.txt", "content2");
-			assertTrue(file2.setLastModified(file2.lastModified() - 5000));
+			TimeUtil.setLastModifiedWithOffset(file2.toPath(), -5000L);
 			File file3 = writeTrashFile("file3.txt", "content3");
-			assertTrue(file3.setLastModified(file3.lastModified() - 5000));
+			TimeUtil.setLastModifiedWithOffset(file3.toPath(), -5000L);
 
 			assertNotNull(git.add().addFilepattern("file1.txt")
 					.addFilepattern("file2.txt").addFilepattern("file3.txt").call());
@@ -346,11 +347,12 @@ public void commitUpdatesSmudgedEntries() throws Exception {
 			assertEquals(0, cache.getEntry("file2.txt").getLength());
 			assertEquals(0, cache.getEntry("file3.txt").getLength());
 
-			long indexTime = db.getIndexFile().lastModified();
+			TimeUtil.setLastModifiedWithOffset(db.getIndexFile().toPath(),
-			db.getIndexFile().setLastModified(indexTime - 5000);
+					-5000L);
 
 			write(file1, "content4");
-			assertTrue(file1.setLastModified(file1.lastModified() + 2500));
+
+			TimeUtil.setLastModifiedWithOffset(file1.toPath(), 2500L);
 			assertNotNull(git.commit().setMessage("edit file").setOnly("file1.txt")
 					.call());
 
@@ -368,9 +370,9 @@ public void commitUpdatesSmudgedEntries() throws Exception {
 	public void commitIgnoresSmudgedEntryWithDifferentId() throws Exception {
 		try (Git git = new Git(db)) {
 			File file1 = writeTrashFile("file1.txt", "content1");
-			assertTrue(file1.setLastModified(file1.lastModified() - 5000));
+			TimeUtil.setLastModifiedWithOffset(file1.toPath(), -5000L);
 			File file2 = writeTrashFile("file2.txt", "content2");
-			assertTrue(file2.setLastModified(file2.lastModified() - 5000));
+			TimeUtil.setLastModifiedWithOffset(file2.toPath(), -5000L);
 
 			assertNotNull(git.add().addFilepattern("file1.txt")
 					.addFilepattern("file2.txt").call());
@@ -399,11 +401,11 @@ public void commitIgnoresSmudgedEntryWithDifferentId() throws Exception {
 			assertEquals(0, cache.getEntry("file1.txt").getLength());
 			assertEquals(0, cache.getEntry("file2.txt").getLength());
 
-			long indexTime = db.getIndexFile().lastModified();
+			TimeUtil.setLastModifiedWithOffset(db.getIndexFile().toPath(),
-			db.getIndexFile().setLastModified(indexTime - 5000);
+					-5000L);
 
 			write(file1, "content5");
-			assertTrue(file1.setLastModified(file1.lastModified() + 1000));
+			TimeUtil.setLastModifiedWithOffset(file1.toPath(), 1000L);
 
 			assertNotNull(git.commit().setMessage("edit file").setOnly("file1.txt")
 					.call());

org.eclipse.jgit.test/tst/org/eclipse/jgit/api/DiffCommandTest.java

@@ -44,7 +44,6 @@
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
 
 import java.io.ByteArrayOutputStream;
 import java.io.File;
@@ -55,6 +54,7 @@
 import org.eclipse.jgit.diff.DiffEntry;
 import org.eclipse.jgit.diff.DiffEntry.ChangeType;
 import org.eclipse.jgit.junit.RepositoryTestCase;
+import org.eclipse.jgit.junit.time.TimeUtil;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.ObjectReader;
 import org.eclipse.jgit.revwalk.RevWalk;
@@ -230,7 +230,7 @@ public void testDiffWithNegativeLineCount() throws Exception {
 	@Test
 	public void testNoOutputStreamSet() throws Exception {
 		File file = writeTrashFile("test.txt", "a");
-		assertTrue(file.setLastModified(file.lastModified() - 5000));
+		TimeUtil.setLastModifiedWithOffset(file.toPath(), -5000L);
 		try (Git git = new Git(db)) {
 			git.add().addFilepattern(".").call();
 			write(file, "b");

org.eclipse.jgit.test/tst/org/eclipse/jgit/api/ResetCommandTest.java

@@ -42,6 +42,7 @@
  */
 package org.eclipse.jgit.api;
 
+import static java.time.Instant.EPOCH;
 import static org.eclipse.jgit.api.ResetCommand.ResetType.HARD;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
@@ -52,6 +53,9 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.attribute.FileTime;
+import java.time.Instant;
 
 import org.eclipse.jgit.api.ResetCommand.ResetType;
 import org.eclipse.jgit.api.errors.GitAPIException;
@@ -246,13 +250,13 @@ public void testMixedReset() throws JGitInternalException,
 	public void testMixedResetRetainsSizeAndModifiedTime() throws Exception {
 		git = new Git(db);
 
-		writeTrashFile("a.txt", "a").setLastModified(
+		Files.setLastModifiedTime(writeTrashFile("a.txt", "a").toPath(),
-				System.currentTimeMillis() - 60 * 1000);
+				FileTime.from(Instant.now().minusSeconds(60)));
 		assertNotNull(git.add().addFilepattern("a.txt").call());
 		assertNotNull(git.commit().setMessage("a commit").call());
 
-		writeTrashFile("b.txt", "b").setLastModified(
+		Files.setLastModifiedTime(writeTrashFile("b.txt", "b").toPath(),
-				System.currentTimeMillis() - 60 * 1000);
+				FileTime.from(Instant.now().minusSeconds(60)));
 		assertNotNull(git.add().addFilepattern("b.txt").call());
 		RevCommit commit2 = git.commit().setMessage("b commit").call();
 		assertNotNull(commit2);
@@ -262,12 +266,12 @@ public void testMixedResetRetainsSizeAndModifiedTime() throws Exception {
 		DirCacheEntry aEntry = cache.getEntry("a.txt");
 		assertNotNull(aEntry);
 		assertTrue(aEntry.getLength() > 0);
-		assertTrue(aEntry.getLastModified() > 0);
+		assertTrue(aEntry.getLastModifiedInstant().compareTo(EPOCH) > 0);
 
 		DirCacheEntry bEntry = cache.getEntry("b.txt");
 		assertNotNull(bEntry);
 		assertTrue(bEntry.getLength() > 0);
-		assertTrue(bEntry.getLastModified() > 0);
+		assertTrue(bEntry.getLastModifiedInstant().compareTo(EPOCH) > 0);
 
 		assertSameAsHead(git.reset().setMode(ResetType.MIXED)
 				.setRef(commit2.getName()).call());
@@ -276,13 +280,17 @@ public void testMixedResetRetainsSizeAndModifiedTime() throws Exception {
 
 		DirCacheEntry mixedAEntry = cache.getEntry("a.txt");
 		assertNotNull(mixedAEntry);
-		assertEquals(aEntry.getLastModified(), mixedAEntry.getLastModified());
+		assertEquals(aEntry.getLastModifiedInstant(),
-		assertEquals(aEntry.getLastModified(), mixedAEntry.getLastModified());
+				mixedAEntry.getLastModifiedInstant());
+		assertEquals(aEntry.getLastModifiedInstant(),
+				mixedAEntry.getLastModifiedInstant());
 
 		DirCacheEntry mixedBEntry = cache.getEntry("b.txt");
 		assertNotNull(mixedBEntry);
-		assertEquals(bEntry.getLastModified(), mixedBEntry.getLastModified());
+		assertEquals(bEntry.getLastModifiedInstant(),
-		assertEquals(bEntry.getLastModified(), mixedBEntry.getLastModified());
+				mixedBEntry.getLastModifiedInstant());
+		assertEquals(bEntry.getLastModifiedInstant(),
+				mixedBEntry.getLastModifiedInstant());
 	}
 
 	@Test

org.eclipse.jgit.test/tst/org/eclipse/jgit/dircache/DirCacheBuilderTest.java

@@ -53,6 +53,7 @@
 import static org.junit.Assert.fail;
 
 import java.io.File;
+import java.time.Instant;
 
 import org.eclipse.jgit.events.IndexChangedEvent;
 import org.eclipse.jgit.events.IndexChangedListener;
@@ -98,7 +99,7 @@ public void testBuildRejectsUnsetFileMode() throws Exception {
 	public void testBuildOneFile_FinishWriteCommit() throws Exception {
 		final String path = "a-file-path";
 		final FileMode mode = FileMode.REGULAR_FILE;
-		final long lastModified = 1218123387057L;
+		final Instant lastModified = Instant.ofEpochMilli(1218123387057L);
 		final int length = 1342;
 		final DirCacheEntry entOrig;
 		{
@@ -116,7 +117,7 @@ public void testBuildOneFile_FinishWriteCommit() throws Exception {
 			assertEquals(ObjectId.zeroId(), entOrig.getObjectId());
 			assertEquals(mode.getBits(), entOrig.getRawMode());
 			assertEquals(0, entOrig.getStage());
-			assertEquals(lastModified, entOrig.getLastModified());
+			assertEquals(lastModified, entOrig.getLastModifiedInstant());
 			assertEquals(length, entOrig.getLength());
 			assertFalse(entOrig.isAssumeValid());
 			b.add(entOrig);
@@ -138,7 +139,7 @@ public void testBuildOneFile_FinishWriteCommit() throws Exception {
 			assertEquals(ObjectId.zeroId(), entOrig.getObjectId());
 			assertEquals(mode.getBits(), entOrig.getRawMode());
 			assertEquals(0, entOrig.getStage());
-			assertEquals(lastModified, entOrig.getLastModified());
+			assertEquals(lastModified, entOrig.getLastModifiedInstant());
 			assertEquals(length, entOrig.getLength());
 			assertFalse(entOrig.isAssumeValid());
 		}
@@ -148,7 +149,7 @@ public void testBuildOneFile_FinishWriteCommit() throws Exception {
 	public void testBuildOneFile_Commit() throws Exception {
 		final String path = "a-file-path";
 		final FileMode mode = FileMode.REGULAR_FILE;
-		final long lastModified = 1218123387057L;
+		final Instant lastModified = Instant.ofEpochMilli(1218123387057L);
 		final int length = 1342;
 		final DirCacheEntry entOrig;
 		{
@@ -166,7 +167,7 @@ public void testBuildOneFile_Commit() throws Exception {
 			assertEquals(ObjectId.zeroId(), entOrig.getObjectId());
 			assertEquals(mode.getBits(), entOrig.getRawMode());
 			assertEquals(0, entOrig.getStage());
-			assertEquals(lastModified, entOrig.getLastModified());
+			assertEquals(lastModified, entOrig.getLastModifiedInstant());
 			assertEquals(length, entOrig.getLength());
 			assertFalse(entOrig.isAssumeValid());
 			b.add(entOrig);
@@ -186,7 +187,7 @@ public void testBuildOneFile_Commit() throws Exception {
 			assertEquals(ObjectId.zeroId(), entOrig.getObjectId());
 			assertEquals(mode.getBits(), entOrig.getRawMode());
 			assertEquals(0, entOrig.getStage());
-			assertEquals(lastModified, entOrig.getLastModified());
+			assertEquals(lastModified, entOrig.getLastModifiedInstant());
 			assertEquals(length, entOrig.getLength());
 			assertFalse(entOrig.isAssumeValid());
 		}
@@ -203,7 +204,7 @@ final class ReceivedEventMarkerException extends RuntimeException {
 		final String path = "a-file-path";
 		final FileMode mode = FileMode.REGULAR_FILE;
 		// "old" date in 2008
-		final long lastModified = 1218123387057L;
+		final Instant lastModified = Instant.ofEpochMilli(1218123387057L);
 		final int length = 1342;
 		DirCacheEntry entOrig;
 		boolean receivedEvent = false;

org.eclipse.jgit.test/tst/org/eclipse/jgit/dircache/DirCacheEntryTest.java

@@ -43,6 +43,7 @@
 
 package org.eclipse.jgit.dircache;
 
+import static java.time.Instant.EPOCH;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertSame;
@@ -188,7 +189,7 @@ private static void copyMetaDataHelper(boolean keepStage) {
 		e.setAssumeValid(false);
 		e.setCreationTime(2L);
 		e.setFileMode(FileMode.EXECUTABLE_FILE);
-		e.setLastModified(3L);
+		e.setLastModified(EPOCH.plusMillis(3L));
 		e.setLength(100L);
 		e.setObjectId(ObjectId
 				.fromString("0123456789012345678901234567890123456789"));
@@ -199,7 +200,7 @@ private static void copyMetaDataHelper(boolean keepStage) {
 		f.setAssumeValid(true);
 		f.setCreationTime(10L);
 		f.setFileMode(FileMode.SYMLINK);
-		f.setLastModified(20L);
+		f.setLastModified(EPOCH.plusMillis(20L));
 		f.setLength(100000000L);
 		f.setObjectId(ObjectId
 				.fromString("1234567890123456789012345678901234567890"));
@@ -212,7 +213,7 @@ private static void copyMetaDataHelper(boolean keepStage) {
 				ObjectId.fromString("1234567890123456789012345678901234567890"),
 				e.getObjectId());
 		assertEquals(FileMode.SYMLINK, e.getFileMode());
-		assertEquals(20L, e.getLastModified());
+		assertEquals(EPOCH.plusMillis(20L), e.getLastModifiedInstant());
 		assertEquals(100000000L, e.getLength());
 		if (keepStage)
 			assertEquals(DirCacheEntry.STAGE_2, e.getStage());

org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/ConcurrentRepackTest.java

@@ -56,6 +56,7 @@
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
+import java.time.Instant;
 
 import org.eclipse.jgit.errors.IncorrectObjectTypeException;
 import org.eclipse.jgit.errors.MissingObjectException;
@@ -71,6 +72,7 @@
 import org.eclipse.jgit.revwalk.RevObject;
 import org.eclipse.jgit.revwalk.RevWalk;
 import org.eclipse.jgit.storage.file.WindowCacheConfig;
+import org.eclipse.jgit.util.FS;
 import org.eclipse.jgit.util.FileUtils;
 import org.junit.After;
 import org.junit.Before;
@@ -235,7 +237,8 @@ private File[] pack(Repository src, RevObject... list)
 
 	private static void write(File[] files, PackWriter pw)
 			throws IOException {
-		final long begin = files[0].getParentFile().lastModified();
+		final Instant begin = FS.DETECTED
+				.lastModifiedInstant(files[0].getParentFile());
 		NullProgressMonitor m = NullProgressMonitor.INSTANCE;
 
 		try (OutputStream out = new BufferedOutputStream(
@@ -252,7 +255,8 @@ private static void write(File[] files, PackWriter pw)
 	}
 
 	private static void delete(File[] list) throws IOException {
-		final long begin = list[0].getParentFile().lastModified();
+		final Instant begin = FS.DETECTED
+				.lastModifiedInstant(list[0].getParentFile());
 		for (File f : list) {
 			FileUtils.delete(f);
 			assertFalse(f + " was removed", f.exists());
@@ -260,14 +264,14 @@ private static void delete(File[] list) throws IOException {
 		touch(begin, list[0].getParentFile());
 	}
 
-	private static void touch(long begin, File dir) {
+	private static void touch(Instant begin, File dir) throws IOException {
-		while (begin >= dir.lastModified()) {
+		while (begin.compareTo(FS.DETECTED.lastModifiedInstant(dir)) >= 0) {
 			try {
 				Thread.sleep(25);
 			} catch (InterruptedException ie) {
 				//
 			}
-			dir.setLastModified(System.currentTimeMillis());
+			FS.DETECTED.setLastModified(dir.toPath(), Instant.now());
 		}
 	}
 

org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/FileSnapshotTest.java

@@ -51,9 +51,11 @@
 import java.nio.file.Files;
 import java.nio.file.StandardCopyOption;
 import java.nio.file.attribute.FileTime;
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.List;
 
+import org.eclipse.jgit.util.FS;
 import org.eclipse.jgit.util.FileUtils;
 import org.eclipse.jgit.util.SystemReader;
 import org.junit.After;
@@ -80,11 +82,12 @@ public void tearDown() throws Exception {
 		FileUtils.delete(trash, FileUtils.RECURSIVE | FileUtils.SKIP_MISSING);
 	}
 
-	private static void waitNextSec(File f) {
+	private static void waitNextTick(File f) throws IOException {
-		long initialLastModified = f.lastModified();
+		Instant initialLastModified = FS.DETECTED.lastModifiedInstant(f);
 		do {
-			f.setLastModified(System.currentTimeMillis());
+			FS.DETECTED.setLastModified(f.toPath(), Instant.now());
-		} while (f.lastModified() == initialLastModified);
+		} while (FS.DETECTED.lastModifiedInstant(f)
+				.equals(initialLastModified));
 	}
 
 	/**
@@ -95,10 +98,10 @@ private static void waitNextSec(File f) {
 	@Test
 	public void testActuallyIsModifiedTrivial() throws Exception {
 		File f1 = createFile("simple");
-		waitNextSec(f1);
+		waitNextTick(f1);
 		FileSnapshot save = FileSnapshot.save(f1);
 		append(f1, (byte) 'x');
-		waitNextSec(f1);
+		waitNextTick(f1);
 		assertTrue(save.isModified(f1));
 	}
 
@@ -113,7 +116,7 @@ public void testActuallyIsModifiedTrivial() throws Exception {
 	@Test
 	public void testNewFileWithWait() throws Exception {
 		File f1 = createFile("newfile");
-		waitNextSec(f1);
+		waitNextTick(f1);
 		FileSnapshot save = FileSnapshot.save(f1);
 		Thread.sleep(1500);
 		assertTrue(save.isModified(f1));
@@ -146,8 +149,8 @@ public void testSimulatePackfileReplacement() throws Exception {
 		File f2 = createFile("fool"); // Guarantees new inode x
 		// wait on f2 since this method resets lastModified of the file
 		// and leaves lastModified of f1 untouched
-		waitNextSec(f2);
+		waitNextTick(f2);
-		waitNextSec(f2);
+		waitNextTick(f2);
 		FileTime timestamp = Files.getLastModifiedTime(f1.toPath());
 		FileSnapshot save = FileSnapshot.save(f1);
 		Files.move(f2.toPath(), f1.toPath(), // Now "file" is inode x
@@ -185,7 +188,7 @@ public void fileSnapshotEquals() throws Exception {
 		// 0 sized FileSnapshot.
 		FileSnapshot fs1 = FileSnapshot.MISSING_FILE;
 		// UNKNOWN_SIZE FileSnapshot.
-		FileSnapshot fs2 = FileSnapshot.save(fs1.lastModified());
+		FileSnapshot fs2 = FileSnapshot.save(fs1.lastModifiedInstant());
 
 		assertTrue(fs1.equals(fs2));
 		assertTrue(fs2.equals(fs1));

org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/GcTestCase.java

@@ -147,9 +147,10 @@ protected RevCommit commitChain(int depth, int width) throws Exception {
 		return tip;
 	}
 
-	protected long lastModified(AnyObjectId objectId) throws IOException {
+	protected long lastModified(AnyObjectId objectId) {
-		return repo.getFS().lastModified(
+		return repo.getFS()
-				repo.getObjectDatabase().fileFor(objectId));
+				.lastModifiedInstant(repo.getObjectDatabase().fileFor(objectId))
+				.toEpochMilli();
 	}
 
 	protected static void fsTick() throws InterruptedException, IOException {

org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/ObjectDirectoryTest.java

@@ -65,6 +65,7 @@
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.storage.file.FileBasedConfig;
+import org.eclipse.jgit.util.FS;
 import org.junit.Assume;
 import org.junit.Rule;
 import org.junit.Test;
@@ -157,13 +158,14 @@ public void testScanningForPackfiles() throws Exception {
 
 			// To deal with racy-git situations JGit's Filesnapshot class will
 			// report a file/folder potentially dirty if
-			// cachedLastReadTime-cachedLastModificationTime < 2500ms. This
+			// cachedLastReadTime-cachedLastModificationTime < filesystem
-			// causes JGit to always rescan a file after modification. But:
+			// timestamp resolution. This causes JGit to always rescan a file
-			// this was true only if the difference between current system time
+			// after modification. But: this was true only if the difference
-			// and cachedLastModification time was less than 2500ms. If the
+			// between current system time and cachedLastModification time was
-			// modification is more than 2500ms ago we may have reported a
+			// less than 2500ms. If the modification is more than 2500ms ago we
-			// file/folder to be clean although it has not been rescanned. A
+			// may have reported a file/folder to be clean although it has not
-			// Bug. To show the bug we sleep for more than 2500ms
+			// been rescanned. A bug. To show the bug we sleep for more than
+			// 2500ms
 			Thread.sleep(2600);
 
 			File[] ret = packsFolder.listFiles(new FilenameFilter() {
@@ -173,7 +175,9 @@ public boolean accept(File dir, String name) {
 				}
 			});
 			assertTrue(ret != null && ret.length == 1);
-			Assume.assumeTrue(tmpFile.lastModified() == ret[0].lastModified());
+			FS fs = db.getFS();
+			Assume.assumeTrue(fs.lastModifiedInstant(tmpFile)
+					.equals(fs.lastModifiedInstant(ret[0])));
 
 			// all objects are in a new packfile but we will not detect it
 			assertFalse(receivingDB.hasObject(unknownID));

org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/PackFileSnapshotTest.java

@@ -59,6 +59,7 @@
 import java.nio.file.StandardOpenOption;
 //import java.nio.file.attribute.BasicFileAttributes;
 import java.text.ParseException;
+import java.time.Instant;
 import java.util.Collection;
 import java.util.Iterator;
 import java.util.Random;
@@ -80,6 +81,7 @@
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.storage.file.FileBasedConfig;
 import org.eclipse.jgit.storage.pack.PackConfig;
+import org.eclipse.jgit.util.FS;
 import org.junit.Test;
 
 public class PackFileSnapshotTest extends RepositoryTestCase {
@@ -188,7 +190,8 @@ public void testDetectModificationAlthoughSameSizeAndModificationtime()
 		AnyObjectId chk1 = pf.getPackChecksum();
 		String name = pf.getPackName();
 		Long length = Long.valueOf(pf.getPackFile().length());
-		long m1 = packFilePath.toFile().lastModified();
+		FS fs = db.getFS();
+		Instant m1 = fs.lastModifiedInstant(packFilePath);
 
 		// Wait for a filesystem timer tick to enhance probability the rest of
 		// this test is done before the filesystem timer ticks again.
@@ -198,15 +201,15 @@ public void testDetectModificationAlthoughSameSizeAndModificationtime()
 		// content and checksum are different since compression level differs
 		AnyObjectId chk2 = repackAndCheck(6, name, length, chk1)
 				.getPackChecksum();
-		long m2 = packFilePath.toFile().lastModified();
+		Instant m2 = fs.lastModifiedInstant(packFilePath);
-		assumeFalse(m2 == m1);
+		assumeFalse(m2.equals(m1));
 
 		// Repack to create packfile with same name, length. Lastmodified is
 		// equal to the previous one because we are in the same filesystem timer
 		// slot. Content and its checksum are different
 		AnyObjectId chk3 = repackAndCheck(7, name, length, chk2)
 				.getPackChecksum();
-		long m3 = packFilePath.toFile().lastModified();
+		Instant m3 = fs.lastModifiedInstant(packFilePath);
 
 		// ask for an unknown git object to force jgit to rescan the list of
 		// available packs. If we would ask for a known objectid then JGit would
@@ -214,7 +217,7 @@ public void testDetectModificationAlthoughSameSizeAndModificationtime()
 		db.getObjectDatabase().has(unknownID);
 		assertEquals(chk3, getSinglePack(db.getObjectDatabase().getPacks())
 				.getPackChecksum());
-		assumeTrue(m3 == m2);
+		assumeTrue(m3.equals(m2));
 	}
 
 	// Try repacking so fast that we get two new packs which differ only in
@@ -253,7 +256,8 @@ public void testDetectModificationAlthoughSameSizeAndModificationtimeAndFileKey(
 		// Repack to create third packfile
 		AnyObjectId chk3 = repackAndCheck(7, name, length, chk2)
 				.getPackChecksum();
-		long m3 = packFilePath.toFile().lastModified();
+		FS fs = db.getFS();
+		Instant m3 = fs.lastModifiedInstant(packFilePath);
 		db.getObjectDatabase().has(unknownID);
 		assertEquals(chk3, getSinglePack(db.getObjectDatabase().getPacks())
 				.getPackChecksum());
@@ -265,8 +269,8 @@ public void testDetectModificationAlthoughSameSizeAndModificationtimeAndFileKey(
 		// Copy copy2 to packfile data to force modification of packfile without
 		// changing the packfile's filekey.
 		copyPack(packFileBasePath, ".copy2", "");
-		long m2 = packFilePath.toFile().lastModified();
+		Instant m2 = fs.lastModifiedInstant(packFilePath);
-		assumeFalse(m3 == m2);
+		assumeFalse(m3.equals(m2));
 
 		db.getObjectDatabase().has(unknownID);
 		assertEquals(chk2, getSinglePack(db.getObjectDatabase().getPacks())
@@ -275,8 +279,8 @@ public void testDetectModificationAlthoughSameSizeAndModificationtimeAndFileKey(
 		// Copy copy2 to packfile data to force modification of packfile without
 		// changing the packfile's filekey.
 		copyPack(packFileBasePath, ".copy1", "");
-		long m1 = packFilePath.toFile().lastModified();
+		Instant m1 = fs.lastModifiedInstant(packFilePath);
-		assumeTrue(m2 == m1);
+		assumeTrue(m2.equals(m1));
 		db.getObjectDatabase().has(unknownID);
 		assertEquals(chk1, getSinglePack(db.getObjectDatabase().getPacks())
 				.getPackChecksum());

org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/RefDirectoryTest.java

@@ -59,6 +59,7 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Map;
@@ -78,6 +79,7 @@
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.revwalk.RevTag;
+import org.eclipse.jgit.util.FS;
 import org.junit.Before;
 import org.junit.Test;
 
@@ -1319,10 +1321,8 @@ private void writePackedRef(String name, AnyObjectId id) throws IOException {
 	private void writePackedRefs(String content) throws IOException {
 		File pr = new File(diskRepo.getDirectory(), "packed-refs");
 		write(pr, content);
-
+		FS fs = diskRepo.getFS();
-		final long now = System.currentTimeMillis();
+		fs.setLastModified(pr.toPath(), Instant.now().minusSeconds(3600));
-		final int oneHourAgo = 3600 * 1000;
-		pr.setLastModified(now - oneHourAgo);
 	}
 
 	private void deleteLooseRef(String name) {

org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/T0003_BasicTest.java

@@ -59,6 +59,7 @@
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.UnsupportedEncodingException;
+import java.time.Instant;
 
 import org.eclipse.jgit.errors.ConfigInvalidException;
 import org.eclipse.jgit.errors.IncorrectObjectTypeException;
@@ -82,6 +83,7 @@
 import org.eclipse.jgit.storage.file.FileBasedConfig;
 import org.eclipse.jgit.storage.file.FileRepositoryBuilder;
 import org.eclipse.jgit.test.resources.SampleDataRepositoryTestCase;
+import org.eclipse.jgit.util.FS;
 import org.eclipse.jgit.util.FileUtils;
 import org.eclipse.jgit.util.IO;
 import org.junit.Rule;
@@ -790,12 +792,14 @@ private RevTag parseTag(AnyObjectId id) throws MissingObjectException,
 	 *
 	 * @param name
 	 *            the file in the repository to force a time change on.
+	 * @throws IOException
 	 */
-	private void BUG_WorkAroundRacyGitIssues(String name) {
+	private void BUG_WorkAroundRacyGitIssues(String name) throws IOException {
 		File path = new File(db.getDirectory(), name);
-		long old = path.lastModified();
+		FS fs = db.getFS();
+		Instant old = fs.lastModifiedInstant(path);
 		long set = 1250379778668L; // Sat Aug 15 20:12:58 GMT-03:30 2009
-		path.setLastModified(set);
+		fs.setLastModified(path.toPath(), Instant.ofEpochMilli(set));
-		assertTrue("time changed", old != path.lastModified());
+		assertFalse("time changed", old.equals(fs.lastModifiedInstant(path)));
 	}
 }

org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/IndexModificationTimesTest.java

@@ -37,8 +37,12 @@
  */
 package org.eclipse.jgit.lib;
 
+import static java.time.Instant.EPOCH;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
+import java.time.Instant;
+
 import org.eclipse.jgit.api.Git;
 import org.eclipse.jgit.dircache.DirCache;
 import org.eclipse.jgit.dircache.DirCacheEntry;
@@ -63,11 +67,11 @@ public void testLastModifiedTimes() throws Exception {
 			DirCacheEntry entry = dc.getEntry(path);
 			DirCacheEntry entry2 = dc.getEntry(path);
 
-			assertTrue("last modified shall not be zero!",
+			assertFalse("last modified shall not be the epoch!",
-					entry.getLastModified() != 0);
+					entry.getLastModifiedInstant().equals(EPOCH));
 
-			assertTrue("last modified shall not be zero!",
+			assertFalse("last modified shall not be the epoch!",
-					entry2.getLastModified() != 0);
+					entry2.getLastModifiedInstant().equals(EPOCH));
 
 			writeTrashFile(path, "new content");
 			git.add().addFilepattern(path).call();
@@ -77,11 +81,11 @@ public void testLastModifiedTimes() throws Exception {
 			entry = dc.getEntry(path);
 			entry2 = dc.getEntry(path);
 
-			assertTrue("last modified shall not be zero!",
+			assertFalse("last modified shall not be the epoch!",
-					entry.getLastModified() != 0);
+					entry.getLastModifiedInstant().equals(EPOCH));
 
-			assertTrue("last modified shall not be zero!",
+			assertFalse("last modified shall not be the epoch!",
-					entry2.getLastModified() != 0);
+					entry2.getLastModifiedInstant().equals(EPOCH));
 		}
 	}
 
@@ -97,7 +101,7 @@ public void testModify() throws Exception {
 			DirCache dc = db.readDirCache();
 			DirCacheEntry entry = dc.getEntry(path);
 
-			long masterLastMod = entry.getLastModified();
+			Instant masterLastMod = entry.getLastModifiedInstant();
 
 			git.checkout().setCreateBranch(true).setName("side").call();
 
@@ -110,7 +114,7 @@ public void testModify() throws Exception {
 			dc = db.readDirCache();
 			entry = dc.getEntry(path);
 
-			long sideLastMode = entry.getLastModified();
+			Instant sideLastMod = entry.getLastModifiedInstant();
 
 			Thread.sleep(2000);
 
@@ -120,9 +124,10 @@ public void testModify() throws Exception {
 			dc = db.readDirCache();
 			entry = dc.getEntry(path);
 
-			assertTrue("shall have equal mod time!", masterLastMod == sideLastMode);
+			assertTrue("shall have equal mod time!",
-			assertTrue("shall not equal master timestamp!",
+					masterLastMod.equals(sideLastMod));
-					entry.getLastModified() == masterLastMod);
+			assertTrue("shall have equal master timestamp!",
+					entry.getLastModifiedInstant().equals(masterLastMod));
 		}
 	}
 

org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/RacyGitTests.java

@@ -50,12 +50,15 @@
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
+import java.time.Instant;
 
 import org.eclipse.jgit.api.Git;
 import org.eclipse.jgit.dircache.DirCache;
 import org.eclipse.jgit.junit.RepositoryTestCase;
+import org.eclipse.jgit.junit.time.TimeUtil;
 import org.eclipse.jgit.treewalk.FileTreeIterator;
 import org.eclipse.jgit.treewalk.WorkingTreeOptions;
+import org.eclipse.jgit.util.FS;
 import org.junit.Test;
 
 public class RacyGitTests extends RepositoryTestCase {
@@ -74,8 +77,8 @@ public void testRacyGitDetection() throws Exception {
 		// create two files
 		File a = writeToWorkDir("a", "a");
 		File b = writeToWorkDir("b", "b");
-		assertTrue(a.setLastModified(b.lastModified()));
+		TimeUtil.setLastModifiedOf(a.toPath(), b.toPath());
-		assertTrue(b.setLastModified(b.lastModified()));
+		TimeUtil.setLastModifiedOf(b.toPath(), b.toPath());
 
 		// wait to ensure that file-modTimes and therefore index entry modTime
 		// doesn't match the modtime of index-file after next persistance
@@ -97,10 +100,11 @@ public void testRacyGitDetection() throws Exception {
 		// filesystem timestamp resolution. By changing the index file
 		// artificially, we create a fake racy situation.
 		File updatedA = writeToWorkDir("a", "a2");
-		long newLastModified = updatedA.lastModified() + 100;
+		Instant newLastModified = TimeUtil
-		assertTrue(updatedA.setLastModified(newLastModified));
+				.setLastModifiedWithOffset(updatedA.toPath(), 100L);
 		resetIndex(new FileTreeIterator(db));
-		assertTrue(db.getIndexFile().setLastModified(newLastModified));
+		FS.DETECTED.setLastModified(db.getIndexFile().toPath(),
+				newLastModified);
 
 		DirCache dc = db.readDirCache();
 		// check index state: although racily clean a should not be reported as

org.eclipse.jgit.test/tst/org/eclipse/jgit/merge/MergerTest.java

@@ -43,6 +43,7 @@
 package org.eclipse.jgit.merge;
 
 import static java.nio.charset.StandardCharsets.UTF_8;
+import static java.time.Instant.EPOCH;
 import static org.eclipse.jgit.lib.Constants.OBJ_BLOB;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
@@ -54,6 +55,7 @@
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
+import java.time.Instant;
 import java.util.Arrays;
 import java.util.Map;
 
@@ -1090,13 +1092,13 @@ public void checkLockedFilesToBeDeleted(MergeStrategy strategy)
 	@Theory
 	public void checkForCorrectIndex(MergeStrategy strategy) throws Exception {
 		File f;
-		long lastTs4, lastTsIndex;
+		Instant lastTs4, lastTsIndex;
 		Git git = Git.wrap(db);
 		File indexFile = db.getIndexFile();
 
 		// Create initial content and remember when the last file was written.
 		f = writeTrashFiles(false, "orig", "orig", "1\n2\n3", "orig", "orig");
-		lastTs4 = FS.DETECTED.lastModified(f);
+		lastTs4 = FS.DETECTED.lastModifiedInstant(f);
 
 		// add all files, commit and check this doesn't update any working tree
 		// files and that the index is in a new file system timer tick. Make
@@ -1109,8 +1111,9 @@ public void checkForCorrectIndex(MergeStrategy strategy) throws Exception {
 		checkConsistentLastModified("0", "1", "2", "3", "4");
 		checkModificationTimeStampOrder("1", "2", "3", "4", "<.git/index");
 		assertEquals("Commit should not touch working tree file 4", lastTs4,
-				FS.DETECTED.lastModified(new File(db.getWorkTree(), "4")));
+				FS.DETECTED
-		lastTsIndex = FS.DETECTED.lastModified(indexFile);
+						.lastModifiedInstant(new File(db.getWorkTree(), "4")));
+		lastTsIndex = FS.DETECTED.lastModifiedInstant(indexFile);
 
 		// Do modifications on the master branch. Then add and commit. This
 		// should touch only "0", "2 and "3"
@@ -1124,7 +1127,7 @@ public void checkForCorrectIndex(MergeStrategy strategy) throws Exception {
 		checkConsistentLastModified("0", "1", "2", "3", "4");
 		checkModificationTimeStampOrder("1", "4", "*" + lastTs4, "<*"
 				+ lastTsIndex, "<0", "2", "3", "<.git/index");
-		lastTsIndex = FS.DETECTED.lastModified(indexFile);
+		lastTsIndex = FS.DETECTED.lastModifiedInstant(indexFile);
 
 		// Checkout a side branch. This should touch only "0", "2 and "3"
 		fsTick(indexFile);
@@ -1133,7 +1136,7 @@ public void checkForCorrectIndex(MergeStrategy strategy) throws Exception {
 		checkConsistentLastModified("0", "1", "2", "3", "4");
 		checkModificationTimeStampOrder("1", "4", "*" + lastTs4, "<*"
 				+ lastTsIndex, "<0", "2", "3", ".git/index");
-		lastTsIndex = FS.DETECTED.lastModified(indexFile);
+		lastTsIndex = FS.DETECTED.lastModifiedInstant(indexFile);
 
 		// This checkout may have populated worktree and index so fast that we
 		// may have smudged entries now. Check that we have the right content
@@ -1146,13 +1149,13 @@ public void checkForCorrectIndex(MergeStrategy strategy) throws Exception {
 				indexState(CONTENT));
 		fsTick(indexFile);
 		f = writeTrashFiles(false, "orig", "orig", "1\n2\n3", "orig", "orig");
-		lastTs4 = FS.DETECTED.lastModified(f);
+		lastTs4 = FS.DETECTED.lastModifiedInstant(f);
 		fsTick(f);
 		git.add().addFilepattern(".").call();
 		checkConsistentLastModified("0", "1", "2", "3", "4");
 		checkModificationTimeStampOrder("*" + lastTsIndex, "<0", "1", "2", "3",
 				"4", "<.git/index");
-		lastTsIndex = FS.DETECTED.lastModified(indexFile);
+		lastTsIndex = FS.DETECTED.lastModifiedInstant(indexFile);
 
 		// Do modifications on the side branch. Touch only "1", "2 and "3"
 		fsTick(indexFile);
@@ -1163,7 +1166,7 @@ public void checkForCorrectIndex(MergeStrategy strategy) throws Exception {
 		checkConsistentLastModified("0", "1", "2", "3", "4");
 		checkModificationTimeStampOrder("0", "4", "*" + lastTs4, "<*"
 				+ lastTsIndex, "<1", "2", "3", "<.git/index");
-		lastTsIndex = FS.DETECTED.lastModified(indexFile);
+		lastTsIndex = FS.DETECTED.lastModifiedInstant(indexFile);
 
 		// merge master and side. Should only touch "0," "2" and "3"
 		fsTick(indexFile);
@@ -1330,9 +1333,10 @@ private void checkConsistentLastModified(String... pathes)
 			assertEquals(
 					"IndexEntry with path "
 							+ path
-							+ " has lastmodified with is different from the worktree file",
+							+ " has lastmodified which is different from the worktree file",
-					FS.DETECTED.lastModified(new File(workTree, path)), dc.getEntry(path)
+					FS.DETECTED.lastModifiedInstant(new File(workTree, path)),
-							.getLastModified());
+					dc.getEntry(path)
+							.getLastModifiedInstant());
 	}
 
 	// Assert that modification timestamps of working tree files are as
@@ -1341,21 +1345,22 @@ private void checkConsistentLastModified(String... pathes)
 	// then this file must be younger then file i. A path "*<modtime>"
 	// represents a file with a modification time of <modtime>
 	// E.g. ("a", "b", "<c", "f/a.txt") means: a<=b<c<=f/a.txt
-	private void checkModificationTimeStampOrder(String... pathes)
+	private void checkModificationTimeStampOrder(String... pathes) {
-			throws IOException {
+		Instant lastMod = EPOCH;
-		long lastMod = Long.MIN_VALUE;
 		for (String p : pathes) {
 			boolean strong = p.startsWith("<");
 			boolean fixed = p.charAt(strong ? 1 : 0) == '*';
 			p = p.substring((strong ? 1 : 0) + (fixed ? 1 : 0));
-			long curMod = fixed ? Long.valueOf(p).longValue()
+			Instant curMod = fixed ? Instant.parse(p)
-					: FS.DETECTED.lastModified(new File(db.getWorkTree(), p));
+					: FS.DETECTED
-			if (strong)
+							.lastModifiedInstant(new File(db.getWorkTree(), p));
+			if (strong) {
 				assertTrue("path " + p + " is not younger than predecesssor",
-						curMod > lastMod);
+						curMod.compareTo(lastMod) > 0);
-			else
+			} else {
 				assertTrue("path " + p + " is older than predecesssor",
-						curMod >= lastMod);
+						curMod.compareTo(lastMod) >= 0);
+			}
 		}
 	}
 

org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/OpenSshConfigTest.java

@@ -57,10 +57,12 @@
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStreamWriter;
+import java.time.Instant;
 
 import org.eclipse.jgit.junit.RepositoryTestCase;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.transport.OpenSshConfig.Host;
+import org.eclipse.jgit.util.FS;
 import org.eclipse.jgit.util.FileUtils;
 import org.eclipse.jgit.util.SystemReader;
 import org.junit.Before;
@@ -91,13 +93,14 @@ public void setUp() throws Exception {
 	}
 
 	private void config(String data) throws IOException {
-		long lastMtime = configFile.lastModified();
+		FS fs = db.getFS();
+		Instant lastMtime = fs.lastModifiedInstant(configFile);
 		do {
 			try (final OutputStreamWriter fw = new OutputStreamWriter(
 					new FileOutputStream(configFile), UTF_8)) {
 				fw.write(data);
 			}
-		} while (lastMtime == configFile.lastModified());
+		} while (lastMtime.equals(fs.lastModifiedInstant(configFile)));
 	}
 
 	@Test

org.eclipse.jgit.test/tst/org/eclipse/jgit/treewalk/FileTreeIteratorTest.java

@@ -52,6 +52,7 @@
 import java.io.File;
 import java.io.IOException;
 import java.security.MessageDigest;
+import java.time.Instant;
 
 import org.eclipse.jgit.api.Git;
 import org.eclipse.jgit.api.ResetCommand.ResetType;
@@ -86,7 +87,7 @@
 public class FileTreeIteratorTest extends RepositoryTestCase {
 	private final String[] paths = { "a,", "a,b", "a/b", "a0b" };
 
-	private long[] mtime;
+	private Instant[] mtime;
 
 	@Override
 	@Before
@@ -99,11 +100,11 @@ public void setUp() throws Exception {
 		// This should stress the sorting code better than doing it in
 		// the correct order.
 		//
-		mtime = new long[paths.length];
+		mtime = new Instant[paths.length];
 		for (int i = paths.length - 1; i >= 0; i--) {
 			final String s = paths[i];
 			writeTrashFile(s, s);
-			mtime[i] = FS.DETECTED.lastModified(new File(trash, s));
+			mtime[i] = db.getFS().lastModifiedInstant(new File(trash, s));
 		}
 	}
 
@@ -199,7 +200,7 @@ public void testSimpleIterate() throws Exception {
 		assertEquals(FileMode.REGULAR_FILE.getBits(), top.mode);
 		assertEquals(paths[0], nameOf(top));
 		assertEquals(paths[0].length(), top.getEntryLength());
-		assertEquals(mtime[0], top.getEntryLastModified());
+		assertEquals(mtime[0], top.getEntryLastModifiedInstant());
 
 		top.next(1);
 		assertFalse(top.first());
@@ -207,7 +208,7 @@ public void testSimpleIterate() throws Exception {
 		assertEquals(FileMode.REGULAR_FILE.getBits(), top.mode);
 		assertEquals(paths[1], nameOf(top));
 		assertEquals(paths[1].length(), top.getEntryLength());
-		assertEquals(mtime[1], top.getEntryLastModified());
+		assertEquals(mtime[1], top.getEntryLastModifiedInstant());
 
 		top.next(1);
 		assertFalse(top.first());
@@ -222,7 +223,7 @@ public void testSimpleIterate() throws Exception {
 		assertFalse(sub.eof());
 		assertEquals(paths[2], nameOf(sub));
 		assertEquals(paths[2].length(), subfti.getEntryLength());
-		assertEquals(mtime[2], subfti.getEntryLastModified());
+		assertEquals(mtime[2], subfti.getEntryLastModifiedInstant());
 
 		sub.next(1);
 		assertTrue(sub.eof());
@@ -233,7 +234,7 @@ public void testSimpleIterate() throws Exception {
 		assertEquals(FileMode.REGULAR_FILE.getBits(), top.mode);
 		assertEquals(paths[3], nameOf(top));
 		assertEquals(paths[3].length(), top.getEntryLength());
-		assertEquals(mtime[3], top.getEntryLastModified());
+		assertEquals(mtime[3], top.getEntryLastModifiedInstant());
 
 		top.next(1);
 		assertTrue(top.eof());
@@ -345,20 +346,21 @@ public void testIsModifiedSymlinkAsFile() throws Exception {
 	@Test
 	public void testIsModifiedFileSmudged() throws Exception {
 		File f = writeTrashFile("file", "content");
+		FS fs = db.getFS();
 		try (Git git = new Git(db)) {
 			// The idea of this test is to check the smudged handling
 			// Hopefully fsTick will make sure our entry gets smudged
 			fsTick(f);
 			writeTrashFile("file", "content");
-			long lastModified = f.lastModified();
+			Instant lastModified = fs.lastModifiedInstant(f);
 			git.add().addFilepattern("file").call();
 			writeTrashFile("file", "conten2");
-			f.setLastModified(lastModified);
+			fs.setLastModified(f.toPath(), lastModified);
 			// We cannot trust this to go fast enough on
 			// a system with less than one-second lastModified
 			// resolution, so we force the index to have the
 			// same timestamp as the file we look at.
-			db.getIndexFile().setLastModified(lastModified);
+			fs.setLastModified(db.getIndexFile().toPath(), lastModified);
 		}
 		DirCacheEntry dce = db.readDirCache().getEntry("file");
 		FileTreeIterator fti = new FileTreeIterator(trash, db.getFS(), db

org.eclipse.jgit.test/tst/org/eclipse/jgit/util/FSTest.java

@@ -43,6 +43,7 @@
 
 package org.eclipse.jgit.util;
 
+import static java.time.Instant.EPOCH;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
@@ -106,7 +107,7 @@ public void testSymlinkAttributes() throws IOException, InterruptedException {
 		assertTrue(fs.exists(link));
 		String targetName = fs.readSymLink(link);
 		assertEquals("å", targetName);
-		assertTrue(fs.lastModified(link) > 0);
+		assertTrue(fs.lastModifiedInstant(link).compareTo(EPOCH) > 0);
 		assertTrue(fs.exists(link));
 		assertFalse(fs.canExecute(link));
 		assertEquals(2, fs.length(link));
@@ -119,8 +120,9 @@ public void testSymlinkAttributes() throws IOException, InterruptedException {
 		// Now create the link target
 		FileUtils.createNewFile(target);
 		assertTrue(fs.exists(link));
-		assertTrue(fs.lastModified(link) > 0);
+		assertTrue(fs.lastModifiedInstant(link).compareTo(EPOCH) > 0);
-		assertTrue(fs.lastModified(target) > fs.lastModified(link));
+		assertTrue(fs.lastModifiedInstant(target)
+				.compareTo(fs.lastModifiedInstant(link)) > 0);
 		assertFalse(fs.canExecute(link));
 		fs.setExecute(target, true);
 		assertFalse(fs.canExecute(link));

org.eclipse.jgit/.settings/.api_filters

@@ -8,6 +8,20 @@
             </message_arguments>
         </filter>
     </resource>
+    <resource path="src/org/eclipse/jgit/dircache/DirCacheEntry.java" type="org.eclipse.jgit.dircache.DirCacheEntry">
+        <filter id="1142947843">
+            <message_arguments>
+                <message_argument value="5.1.9"/>
+                <message_argument value="getLastModifiedInstant()"/>
+            </message_arguments>
+        </filter>
+        <filter id="1142947843">
+            <message_arguments>
+                <message_argument value="5.1.9"/>
+                <message_argument value="setLastModified(Instant)"/>
+            </message_arguments>
+        </filter>
+    </resource>
     <resource path="src/org/eclipse/jgit/errors/PackInvalidException.java" type="org.eclipse.jgit.errors.PackInvalidException">
         <filter id="1142947843">
             <message_arguments>
@@ -130,6 +144,28 @@
             </message_arguments>
         </filter>
     </resource>
+    <resource path="src/org/eclipse/jgit/treewalk/WorkingTreeIterator.java" type="org.eclipse.jgit.treewalk.WorkingTreeIterator">
+        <filter id="1142947843">
+            <message_arguments>
+                <message_argument value="5.1.9"/>
+                <message_argument value="getEntryLastModifiedInstant()"/>
+            </message_arguments>
+        </filter>
+    </resource>
+    <resource path="src/org/eclipse/jgit/treewalk/WorkingTreeIterator.java" type="org.eclipse.jgit.treewalk.WorkingTreeIterator$Entry">
+        <filter id="336695337">
+            <message_arguments>
+                <message_argument value="org.eclipse.jgit.treewalk.WorkingTreeIterator.Entry"/>
+                <message_argument value="getLastModifiedInstant()"/>
+            </message_arguments>
+        </filter>
+        <filter id="1142947843">
+            <message_arguments>
+                <message_argument value="5.1.9"/>
+                <message_argument value="getLastModifiedInstant()"/>
+            </message_arguments>
+        </filter>
+    </resource>
     <resource path="src/org/eclipse/jgit/util/FS.java" type="org.eclipse.jgit.util.FS">
         <filter id="1142947843">
             <message_arguments>
@@ -137,12 +173,30 @@
                 <message_argument value="fileAttributes(File)"/>
             </message_arguments>
         </filter>
+        <filter id="1142947843">
+            <message_arguments>
+                <message_argument value="5.1.9"/>
+                <message_argument value="lastModifiedInstant(File)"/>
+            </message_arguments>
+        </filter>
+        <filter id="1142947843">
+            <message_arguments>
+                <message_argument value="5.1.9"/>
+                <message_argument value="lastModifiedInstant(Path)"/>
+            </message_arguments>
+        </filter>
         <filter id="1142947843">
             <message_arguments>
                 <message_argument value="5.1.9"/>
                 <message_argument value="setAsyncfileStoreAttrCache(boolean)"/>
             </message_arguments>
         </filter>
+        <filter id="1142947843">
+            <message_arguments>
+                <message_argument value="5.1.9"/>
+                <message_argument value="setLastModified(Path, Instant)"/>
+            </message_arguments>
+        </filter>
         <filter id="1142947843">
             <message_arguments>
                 <message_argument value="5.2.3"/>
@@ -150,6 +204,14 @@
             </message_arguments>
         </filter>
     </resource>
+    <resource path="src/org/eclipse/jgit/util/FS.java" type="org.eclipse.jgit.util.FS$Attributes">
+        <filter id="1142947843">
+            <message_arguments>
+                <message_argument value="5.1.9"/>
+                <message_argument value="getLastModifiedInstant()"/>
+            </message_arguments>
+        </filter>
+    </resource>
     <resource path="src/org/eclipse/jgit/util/FileUtils.java" type="org.eclipse.jgit.util.FileUtils">
         <filter id="1142947843">
             <message_arguments>

org.eclipse.jgit/resources/org/eclipse/jgit/internal/JGitText.properties

@@ -561,6 +561,7 @@ rawLogMessageDoesNotParseAsLogEntry=Raw log message does not parse as log entry
 readConfigFailed=Reading config file ''{0}'' failed
 readerIsRequired=Reader is required
 readingObjectsFromLocalRepositoryFailed=reading objects from local repository failed: {0}
+readLastModifiedFailed=Reading lastModified of {0} failed
 readTimedOut=Read timed out after {0} ms
 receivePackObjectTooLarge1=Object too large, rejecting the pack. Max object size limit is {0} bytes.
 receivePackObjectTooLarge2=Object too large ({0} bytes), rejecting the pack. Max object size limit is {1} bytes.

org.eclipse.jgit/src/org/eclipse/jgit/api/AddCommand.java

@@ -50,6 +50,7 @@
 
 import java.io.IOException;
 import java.io.InputStream;
+import java.time.Instant;
 import java.util.Collection;
 import java.util.LinkedList;
 
@@ -228,7 +229,7 @@ public DirCache call() throws GitAPIException, NoFilepatternException {
 
 				if (GITLINK != mode) {
 					entry.setLength(f.getEntryLength());
-					entry.setLastModified(f.getEntryLastModified());
+					entry.setLastModified(f.getEntryLastModifiedInstant());
 					long len = f.getEntryContentLength();
 					// We read and filter the content multiple times.
 					// f.getEntryContentLength() reads and filters the input and
@@ -241,7 +242,7 @@ public DirCache call() throws GitAPIException, NoFilepatternException {
 					}
 				} else {
 					entry.setLength(0);
-					entry.setLastModified(0);
+					entry.setLastModified(Instant.ofEpochSecond(0));
 					entry.setObjectId(f.getEntryObjectId());
 				}
 				builder.add(entry);

org.eclipse.jgit/src/org/eclipse/jgit/api/CommitCommand.java

@@ -392,7 +392,7 @@ private DirCache createTemporaryIndex(ObjectId headId, DirCache index,
 						final DirCacheEntry dcEntry = new DirCacheEntry(path);
 						long entryLength = fTree.getEntryLength();
 						dcEntry.setLength(entryLength);
-						dcEntry.setLastModified(fTree.getEntryLastModified());
+						dcEntry.setLastModified(fTree.getEntryLastModifiedInstant());
 						dcEntry.setFileMode(fTree.getIndexFileMode(dcTree));
 
 						boolean objectExists = (dcTree != null

org.eclipse.jgit/src/org/eclipse/jgit/api/ResetCommand.java

@@ -422,7 +422,7 @@ private void resetIndex(ObjectId commitTree) throws IOException {
 						DirCacheIterator.class);
 				if (dcIter != null && dcIter.idEqual(cIter)) {
 					DirCacheEntry indexEntry = dcIter.getDirCacheEntry();
-					entry.setLastModified(indexEntry.getLastModified());
+					entry.setLastModified(indexEntry.getLastModifiedInstant());
 					entry.setLength(indexEntry.getLength());
 				}
 

org.eclipse.jgit/src/org/eclipse/jgit/api/StashApplyCommand.java

@@ -332,7 +332,7 @@ private void resetIndex(RevTree tree) throws IOException {
 						DirCacheIterator.class);
 				if (dcIter != null && dcIter.idEqual(cIter)) {
 					DirCacheEntry indexEntry = dcIter.getDirCacheEntry();
-					entry.setLastModified(indexEntry.getLastModified());
+					entry.setLastModified(indexEntry.getLastModifiedInstant());
 					entry.setLength(indexEntry.getLength());
 				}
 

org.eclipse.jgit/src/org/eclipse/jgit/api/StashCreateCommand.java

@@ -300,7 +300,8 @@ public RevCommit call() throws GitAPIException {
 						final DirCacheEntry entry = new DirCacheEntry(
 								treeWalk.getRawPath());
 						entry.setLength(wtIter.getEntryLength());
-						entry.setLastModified(wtIter.getEntryLastModified());
+						entry.setLastModified(
+								wtIter.getEntryLastModifiedInstant());
 						entry.setFileMode(wtIter.getEntryFileMode());
 						long contentLength = wtIter.getEntryContentLength();
 						try (InputStream in = wtIter.openEntryStream()) {

org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCache.java

@@ -497,8 +497,9 @@ else if (ver != 2)
 			throw new CorruptObjectException(JGitText.get().DIRCHasTooManyEntries);
 
 		snapshot = FileSnapshot.save(liveFile);
-		int smudge_s = (int) (snapshot.lastModified() / 1000);
+		// TODO (ms) combine smudge_s and smudge_ns into Duration
-		int smudge_ns = ((int) (snapshot.lastModified() % 1000)) * 1000000;
+		int smudge_s = (int) (snapshot.lastModifiedInstant().getEpochSecond());
+		int smudge_ns = snapshot.lastModifiedInstant().getNano();
 
 		// Load the individual file entries.
 		//
@@ -679,8 +680,8 @@ void writeTo(File dir, OutputStream os) throws IOException {
 			// so we use the current timestamp as a approximation.
 			myLock.createCommitSnapshot();
 			snapshot = myLock.getCommitSnapshot();
-			smudge_s = (int) (snapshot.lastModified() / 1000);
+			smudge_s = (int) (snapshot.lastModifiedInstant().getEpochSecond());
-			smudge_ns = ((int) (snapshot.lastModified() % 1000)) * 1000000;
+			smudge_ns = snapshot.lastModifiedInstant().getNano();
 		} else {
 			// Used in unit tests only
 			smudge_ns = 0;
@@ -1025,7 +1026,7 @@ private void updateSmudgedEntries() throws IOException {
 				DirCacheEntry entry = iIter.getDirCacheEntry();
 				if (entry.isSmudged() && iIter.idEqual(fIter)) {
 					entry.setLength(fIter.getEntryLength());
-					entry.setLastModified(fIter.getEntryLastModified());
+					entry.setLastModified(fIter.getEntryLastModifiedInstant());
 				}
 			}
 		}

org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheCheckout.java

@@ -50,6 +50,7 @@
 import java.io.OutputStream;
 import java.nio.file.StandardCopyOption;
 import java.text.MessageFormat;
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Iterator;
@@ -425,8 +426,10 @@ void processEntry(CanonicalTreeParser m, DirCacheBuildIterator i,
 					// update the timestamp of the index with the one from the
 					// file if not set, as we are sure to be in sync here.
 					DirCacheEntry entry = i.getDirCacheEntry();
-					if (entry.getLastModified() == 0)
+					Instant mtime = entry.getLastModifiedInstant();
-						entry.setLastModified(f.getEntryLastModified());
+					if (mtime == null || mtime.equals(Instant.EPOCH)) {
+						entry.setLastModified(f.getEntryLastModifiedInstant());
+					}
 					keep(entry);
 				}
 			} else
@@ -611,7 +614,7 @@ private void checkoutGitlink(String path, DirCacheEntry entry)
 		File gitlinkDir = new File(repo.getWorkTree(), path);
 		FileUtils.mkdirs(gitlinkDir, true);
 		FS fs = repo.getFS();
-		entry.setLastModified(fs.lastModified(gitlinkDir));
+		entry.setLastModified(fs.lastModifiedInstant(gitlinkDir));
 	}
 
 	private static ArrayList<String> filterOut(ArrayList<String> strings,
@@ -1433,7 +1436,7 @@ public static void checkoutEntry(Repository repo, DirCacheEntry entry,
 			}
 			fs.createSymLink(f, target);
 			entry.setLength(bytes.length);
-			entry.setLastModified(fs.lastModified(f));
+			entry.setLastModified(fs.lastModifiedInstant(f));
 			return;
 		}
 
@@ -1502,7 +1505,7 @@ public static void checkoutEntry(Repository repo, DirCacheEntry entry,
 				FileUtils.delete(tmpFile);
 			}
 		}
-		entry.setLastModified(fs.lastModified(f));
+		entry.setLastModified(fs.lastModifiedInstant(f));
 	}
 
 	// Run an external filter command

org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheEntry.java

@@ -56,6 +56,7 @@
 import java.nio.ByteBuffer;
 import java.security.MessageDigest;
 import java.text.MessageFormat;
+import java.time.Instant;
 import java.util.Arrays;
 
 import org.eclipse.jgit.errors.CorruptObjectException;
@@ -144,6 +145,7 @@ public class DirCacheEntry {
 	/** Flags which are never stored to disk. */
 	private byte inCoreFlags;
 
+	// TODO (ms): use Instant to combine smudge_s and smudge_ns
 	DirCacheEntry(final byte[] sharedInfo, final MutableInteger infoAt,
 			final InputStream in, final MessageDigest md, final int smudge_s,
 			final int smudge_ns) throws IOException {
@@ -563,21 +565,50 @@ public void setCreationTime(long when) {
 	 *
 	 * @return last modification time of this file, in milliseconds since the
 	 *         Java epoch (midnight Jan 1, 1970 UTC).
+	 * @deprecated use {@link #getLastModifiedInstant()} instead
 	 */
+	@Deprecated
 	public long getLastModified() {
 		return decodeTS(P_MTIME);
 	}
 
+	/**
+	 * Get the cached last modification date of this file.
+	 * <p>
+	 * One of the indicators that the file has been modified by an application
+	 * changing the working tree is if the last modification time for the file
+	 * differs from the time stored in this entry.
+	 *
+	 * @return last modification time of this file.
+	 * @since 5.1.9
+	 */
+	public Instant getLastModifiedInstant() {
+		return decodeTSInstant(P_MTIME);
+	}
+
 	/**
 	 * Set the cached last modification date of this file, using milliseconds.
 	 *
 	 * @param when
 	 *            new cached modification date of the file, in milliseconds.
+	 * @deprecated use {@link #setLastModified(Instant)} instead
 	 */
+	@Deprecated
 	public void setLastModified(long when) {
 		encodeTS(P_MTIME, when);
 	}
 
+	/**
+	 * Set the cached last modification date of this file.
+	 *
+	 * @param when
+	 *            new cached modification date of the file.
+	 * @since 5.1.9
+	 */
+	public void setLastModified(Instant when) {
+		encodeTS(P_MTIME, when);
+	}
+
 	/**
 	 * Get the cached size (mod 4 GB) (in bytes) of this file.
 	 * <p>
@@ -692,7 +723,8 @@ public byte[] getRawPath() {
 	@SuppressWarnings("nls")
 	@Override
 	public String toString() {
-		return getFileMode() + " " + getLength() + " " + getLastModified()
+		return getFileMode() + " " + getLength() + " "
+				+ getLastModifiedInstant()
 				+ " " + getObjectId() + " " + getStage() + " "
 				+ getPathString() + "\n";
 	}
@@ -750,12 +782,25 @@ private long decodeTS(int pIdx) {
 		return 1000L * sec + ms;
 	}
 
+	private Instant decodeTSInstant(int pIdx) {
+		final int base = infoOffset + pIdx;
+		final int sec = NB.decodeInt32(info, base);
+		final int nano = NB.decodeInt32(info, base + 4);
+		return Instant.ofEpochSecond(sec, nano);
+	}
+
 	private void encodeTS(int pIdx, long when) {
 		final int base = infoOffset + pIdx;
 		NB.encodeInt32(info, base, (int) (when / 1000));
 		NB.encodeInt32(info, base + 4, ((int) (when % 1000)) * 1000000);
 	}
 
+	private void encodeTS(int pIdx, Instant when) {
+		final int base = infoOffset + pIdx;
+		NB.encodeInt32(info, base, (int) when.getEpochSecond());
+		NB.encodeInt32(info, base + 4, when.getNano());
+	}
+
 	private int getExtendedFlags() {
 		if (isExtended())
 			return NB.decodeUInt16(info, infoOffset + P_FLAGS2) << 16;

org.eclipse.jgit/src/org/eclipse/jgit/internal/JGitText.java

@@ -622,6 +622,7 @@ public static JGitText get() {
 	/***/ public String readConfigFailed;
 	/***/ public String readerIsRequired;
 	/***/ public String readingObjectsFromLocalRepositoryFailed;
+	/***/ public String readLastModifiedFailed;
 	/***/ public String readTimedOut;
 	/***/ public String receivePackObjectTooLarge1;
 	/***/ public String receivePackObjectTooLarge2;

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/FileSnapshot.java

@@ -48,10 +48,10 @@
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.attribute.BasicFileAttributes;
-import java.text.DateFormat;
-import java.text.SimpleDateFormat;
 import java.time.Duration;
-import java.util.Date;
+import java.time.Instant;
+import java.time.ZoneId;
+import java.time.format.DateTimeFormatter;
 import java.util.Locale;
 import java.util.Objects;
 import java.util.concurrent.TimeUnit;
@@ -87,8 +87,14 @@ public class FileSnapshot {
 	 */
 	public static final long UNKNOWN_SIZE = -1;
 
+	private static final Instant UNKNOWN_TIME = Instant.ofEpochMilli(-1);
+
 	private static final Object MISSING_FILEKEY = new Object();
 
+	private static final DateTimeFormatter dateFmt = DateTimeFormatter
+			.ofPattern("yyyy-MM-dd HH:mm:ss.nnnnnnnnn") //$NON-NLS-1$
+			.withLocale(Locale.getDefault()).withZone(ZoneId.systemDefault());
+
 	/**
 	 * A FileSnapshot that is considered to always be modified.
 	 * <p>
@@ -96,8 +102,8 @@ public class FileSnapshot {
 	 * file, but only after {@link #isModified(File)} gets invoked. The returned
 	 * snapshot contains only invalid status information.
 	 */
-	public static final FileSnapshot DIRTY = new FileSnapshot(-1, -1,
+	public static final FileSnapshot DIRTY = new FileSnapshot(UNKNOWN_TIME,
-			UNKNOWN_SIZE, Duration.ZERO, MISSING_FILEKEY);
+			UNKNOWN_TIME, UNKNOWN_SIZE, Duration.ZERO, MISSING_FILEKEY);
 
 	/**
 	 * A FileSnapshot that is clean if the file does not exist.
@@ -106,8 +112,8 @@ public class FileSnapshot {
 	 * file to be clean. {@link #isModified(File)} will return false if the file
 	 * path does not exist.
 	 */
-	public static final FileSnapshot MISSING_FILE = new FileSnapshot(0, 0, 0,
+	public static final FileSnapshot MISSING_FILE = new FileSnapshot(
-			Duration.ZERO, MISSING_FILEKEY) {
+			Instant.EPOCH, Instant.EPOCH, 0, Duration.ZERO, MISSING_FILEKEY) {
 		@Override
 		public boolean isModified(File path) {
 			return FS.DETECTED.exists(path);
@@ -163,18 +169,41 @@ private static Object getFileKey(BasicFileAttributes fileAttributes) {
 	 * @param modified
 	 *            the last modification time of the file
 	 * @return the snapshot.
+	 * @deprecated use {@link #save(Instant)} instead.
 	 */
+	@Deprecated
 	public static FileSnapshot save(long modified) {
-		final long read = System.currentTimeMillis();
+		final Instant read = Instant.now();
+		return new FileSnapshot(read, Instant.ofEpochMilli(modified),
+				UNKNOWN_SIZE, Duration.ZERO, MISSING_FILEKEY);
+	}
+
+	/**
+	 * Record a snapshot for a file for which the last modification time is
+	 * already known.
+	 * <p>
+	 * This method should be invoked before the file is accessed.
+	 * <p>
+	 * Note that this method cannot rely on measuring file timestamp resolution
+	 * to avoid racy git issues caused by finite file timestamp resolution since
+	 * it's unknown in which filesystem the file is located. Hence the worst
+	 * case fallback for timestamp resolution is used.
+	 *
+	 * @param modified
+	 *            the last modification time of the file
+	 * @return the snapshot.
+	 */
+	public static FileSnapshot save(Instant modified) {
+		final Instant read = Instant.now();
 		return new FileSnapshot(read, modified, UNKNOWN_SIZE, Duration.ZERO,
 				MISSING_FILEKEY);
 	}
 
 	/** Last observed modification time of the path. */
-	private final long lastModified;
+	private final Instant lastModified;
 
 	/** Last wall-clock time the path was read. */
-	private volatile long lastRead;
+	private volatile Instant lastRead;
 
 	/** True once {@link #lastRead} is far later than {@link #lastModified}. */
 	private boolean cannotBeRacilyClean;
@@ -222,7 +251,7 @@ protected FileSnapshot(File file) {
 	 */
 	protected FileSnapshot(File file, boolean useConfig) {
 		this.file = file;
-		this.lastRead = System.currentTimeMillis();
+		this.lastRead = Instant.now();
 		this.fsTimestampResolution = useConfig
 				? FS.getFsTimerResolution(file.toPath().getParent())
 				: FALLBACK_TIMESTAMP_RESOLUTION;
@@ -230,18 +259,20 @@ protected FileSnapshot(File file, boolean useConfig) {
 		try {
 			fileAttributes = FS.DETECTED.fileAttributes(file);
 		} catch (IOException e) {
-			this.lastModified = file.lastModified();
+			this.lastModified = Instant.ofEpochMilli(file.lastModified());
 			this.size = file.length();
 			this.fileKey = MISSING_FILEKEY;
 			return;
 		}
-		this.lastModified = fileAttributes.lastModifiedTime().toMillis();
+		this.lastModified = fileAttributes.lastModifiedTime().toInstant();
 		this.size = fileAttributes.size();
 		this.fileKey = getFileKey(fileAttributes);
-		LOG.debug("file={}, create new FileSnapshot: lastRead={} ms" //$NON-NLS-1$
+		if (LOG.isDebugEnabled()) {
-				+ ", lastModified={} ms, size={}, fileKey={}", //$NON-NLS-1$
+			LOG.debug("file={}, create new FileSnapshot: lastRead={}, lastModified={}, size={}, fileKey={}", //$NON-NLS-1$
-				file, Long.valueOf(lastRead), Long.valueOf(lastModified),
+					file, dateFmt.format(lastRead),
-				Long.valueOf(size), fileKey);
+					dateFmt.format(lastModified), Long.valueOf(size),
+					fileKey.toString());
+		}
 	}
 
 	private boolean sizeChanged;
@@ -252,7 +283,7 @@ protected FileSnapshot(File file, boolean useConfig) {
 
 	private boolean wasRacyClean;
 
-	private FileSnapshot(long read, long modified, long size,
+	private FileSnapshot(Instant read, Instant modified, long size,
 			@NonNull Duration fsTimestampResolution, @NonNull Object fileKey) {
 		this.file = null;
 		this.lastRead = read;
@@ -266,8 +297,19 @@ private FileSnapshot(long read, long modified, long size,
 	 * Get time of last snapshot update
 	 *
 	 * @return time of last snapshot update
+	 * @deprecated use {@link #lastModifiedInstant()} instead
 	 */
+	@Deprecated
 	public long lastModified() {
+		return lastModified.toEpochMilli();
+	}
+
+	/**
+	 * Get time of last snapshot update
+	 *
+	 * @return time of last snapshot update
+	 */
+	public Instant lastModifiedInstant() {
 		return lastModified;
 	}
 
@@ -286,16 +328,16 @@ public long size() {
 	 * @return true if the path needs to be read again.
 	 */
 	public boolean isModified(File path) {
-		long currLastModified;
+		Instant currLastModified;
 		long currSize;
 		Object currFileKey;
 		try {
 			BasicFileAttributes fileAttributes = FS.DETECTED.fileAttributes(path);
-			currLastModified = fileAttributes.lastModifiedTime().toMillis();
+			currLastModified = fileAttributes.lastModifiedTime().toInstant();
 			currSize = fileAttributes.size();
 			currFileKey = getFileKey(fileAttributes);
 		} catch (IOException e) {
-			currLastModified = path.lastModified();
+			currLastModified = Instant.ofEpochMilli(path.lastModified());
 			currSize = path.length();
 			currFileKey = MISSING_FILEKEY;
 		}
@@ -337,7 +379,7 @@ public boolean isModified(File path) {
 	 *            the other snapshot.
 	 */
 	public void setClean(FileSnapshot other) {
-		final long now = other.lastRead;
+		final Instant now = other.lastRead;
 		if (!isRacyClean(now)) {
 			cannotBeRacilyClean = true;
 		}
@@ -351,7 +393,7 @@ public void setClean(FileSnapshot other) {
 	 *             if sleep was interrupted
 	 */
 	public void waitUntilNotRacy() throws InterruptedException {
-		while (isRacyClean(System.currentTimeMillis())) {
+		while (isRacyClean(Instant.now())) {
 			TimeUnit.NANOSECONDS
 					.sleep((fsTimestampResolution.toNanos() + 1) * 11 / 10);
 		}
@@ -366,7 +408,7 @@ public void waitUntilNotRacy() throws InterruptedException {
 	 */
 	public boolean equals(FileSnapshot other) {
 		boolean sizeEq = size == UNKNOWN_SIZE || other.size == UNKNOWN_SIZE || size == other.size;
-		return lastModified == other.lastModified && sizeEq
+		return lastModified.equals(other.lastModified) && sizeEq
 				&& Objects.equals(fileKey, other.fileKey);
 	}
 
@@ -389,8 +431,7 @@ public boolean equals(Object obj) {
 	/** {@inheritDoc} */
 	@Override
 	public int hashCode() {
-		return Objects.hash(Long.valueOf(lastModified), Long.valueOf(size),
+		return Objects.hash(lastModified, Long.valueOf(size), fileKey);
-				fileKey);
 	}
 
 	/**
@@ -435,34 +476,37 @@ public String toString() {
 		if (this == MISSING_FILE) {
 			return "MISSING_FILE";
 		}
-		DateFormat f = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS",
+		return "FileSnapshot[modified: " + dateFmt.format(lastModified)
-				Locale.US);
+				+ ", read: " + dateFmt.format(lastRead) + ", size:" + size
-		return "FileSnapshot[modified: " + f.format(new Date(lastModified))
-				+ ", read: " + f.format(new Date(lastRead)) + ", size:" + size
 				+ ", fileKey: " + fileKey + "]";
 	}
 
-	private boolean isRacyClean(long read) {
+	private boolean isRacyClean(Instant read) {
 		// add a 10% safety margin
 		long racyNanos = (fsTimestampResolution.toNanos() + 1) * 11 / 10;
-		long delta = (read - lastModified) * 1_000_000;
+		long delta = Duration.between(lastModified, read).toNanos();
 		wasRacyClean = delta <= racyNanos;
-		LOG.debug("file={}, isRacyClean={}, read={} ms, lastModified={} ms," //$NON-NLS-1$
+		if (LOG.isDebugEnabled()) {
-				+ " delta={} ns, racy<={} ns", //$NON-NLS-1$
+			LOG.debug(
-				file, Boolean.valueOf(wasRacyClean), Long.valueOf(read),
+					"file={}, isRacyClean={}, read={}, lastModified={}, delta={} ns, racy<={} ns", //$NON-NLS-1$
-				Long.valueOf(lastModified), Long.valueOf(delta),
+					file, Boolean.valueOf(wasRacyClean), dateFmt.format(read),
-				Long.valueOf(racyNanos));
+					dateFmt.format(lastModified), Long.valueOf(delta),
+					Long.valueOf(racyNanos));
+		}
 		return wasRacyClean;
 	}
 
-	private boolean isModified(long currLastModified) {
+	private boolean isModified(Instant currLastModified) {
 		// Any difference indicates the path was modified.
 
-		lastModifiedChanged = lastModified != currLastModified;
+		lastModifiedChanged = !lastModified.equals(currLastModified);
 		if (lastModifiedChanged) {
-			LOG.debug("file={}, lastModified changed from {} to {}", //$NON-NLS-1$
+			if (LOG.isDebugEnabled()) {
-					file, Long.valueOf(lastModified),
+				LOG.debug(
-					Long.valueOf(currLastModified));
+						"file={}, lastModified changed from {} to {}", //$NON-NLS-1$
+						file, dateFmt.format(lastModified),
+						dateFmt.format(currLastModified));
+			}
 			return true;
 		}
 

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/GC.java

@@ -372,8 +372,9 @@ private void deleteOldPacks(Collection<PackFile> oldPacks,
 					continue oldPackLoop;
 
 			if (!oldPack.shouldBeKept()
-					&& repo.getFS().lastModified(
+					&& repo.getFS()
-							oldPack.getPackFile()) < packExpireDate) {
+							.lastModifiedInstant(oldPack.getPackFile())
+							.toEpochMilli() < packExpireDate) {
 				oldPack.close();
 				if (shouldLoosen) {
 					loosen(inserter, reader, oldPack, ids);
@@ -561,8 +562,10 @@ public void prune(Set<ObjectId> objectsToKeep) throws IOException,
 					String fName = f.getName();
 					if (fName.length() != Constants.OBJECT_ID_STRING_LENGTH - 2)
 						continue;
-					if (repo.getFS().lastModified(f) >= expireDate)
+					if (repo.getFS().lastModifiedInstant(f)
+							.toEpochMilli() >= expireDate) {
 						continue;
+					}
 					try {
 						ObjectId id = ObjectId.fromString(d + fName);
 						if (objectsToKeep.contains(id))

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/LockFile.java

@@ -56,8 +56,11 @@
 import java.nio.ByteBuffer;
 import java.nio.channels.Channels;
 import java.nio.channels.FileChannel;
+import java.nio.file.Files;
 import java.nio.file.StandardCopyOption;
+import java.nio.file.attribute.FileTime;
 import java.text.MessageFormat;
+import java.time.Instant;
 
 import org.eclipse.jgit.internal.JGitText;
 import org.eclipse.jgit.lib.Constants;
@@ -424,7 +427,12 @@ public void waitForStatChange() throws InterruptedException {
 		FileSnapshot n = FileSnapshot.save(lck);
 		while (o.equals(n)) {
 			Thread.sleep(25 /* milliseconds */);
-			lck.setLastModified(System.currentTimeMillis());
+			try {
+				Files.setLastModifiedTime(lck.toPath(),
+						FileTime.from(Instant.now()));
+			} catch (IOException e) {
+				n.waitUntilNotRacy();
+			}
 			n = FileSnapshot.save(lck);
 		}
 	}
@@ -474,11 +482,22 @@ private void saveStatInformation() {
 	 * Get the modification time of the output file when it was committed.
 	 *
 	 * @return modification time of the lock file right before we committed it.
+	 * @deprecated use {@link #getCommitLastModifiedInstant()} instead
 	 */
+	@Deprecated
 	public long getCommitLastModified() {
 		return commitSnapshot.lastModified();
 	}
 
+	/**
+	 * Get the modification time of the output file when it was committed.
+	 *
+	 * @return modification time of the lock file right before we committed it.
+	 */
+	public Instant getCommitLastModifiedInstant() {
+		return commitSnapshot.lastModifiedInstant();
+	}
+
 	/**
 	 * Get the {@link FileSnapshot} just before commit.
 	 *

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackFile.java

@@ -60,6 +60,7 @@
 import java.nio.file.AccessDeniedException;
 import java.nio.file.NoSuchFileException;
 import java.text.MessageFormat;
+import java.time.Instant;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.Comparator;
@@ -107,7 +108,7 @@ public class PackFile implements Iterable<PackIndex.MutableEntry> {
 	public static final Comparator<PackFile> SORT = new Comparator<PackFile>() {
 		@Override
 		public int compare(PackFile a, PackFile b) {
-			return b.packLastModified - a.packLastModified;
+			return b.packLastModified.compareTo(a.packLastModified);
 		}
 	};
 
@@ -132,7 +133,7 @@ public int compare(PackFile a, PackFile b) {
 
 	private int activeCopyRawData;
 
-	int packLastModified;
+	Instant packLastModified;
 
 	private PackFileSnapshot fileSnapshot;
 
@@ -172,7 +173,7 @@ public int compare(PackFile a, PackFile b) {
 	public PackFile(File packFile, int extensions) {
 		this.packFile = packFile;
 		this.fileSnapshot = PackFileSnapshot.save(packFile);
-		this.packLastModified = (int) (fileSnapshot.lastModified() >> 10);
+		this.packLastModified = fileSnapshot.lastModifiedInstant();
 		this.extensions = extensions;
 
 		// Multiply by 31 here so we can more directly combine with another

org.eclipse.jgit/src/org/eclipse/jgit/merge/ResolveMerger.java

@@ -46,6 +46,7 @@
  */
 package org.eclipse.jgit.merge;
 
+import static java.time.Instant.EPOCH;
 import static org.eclipse.jgit.diff.DiffAlgorithm.SupportedAlgorithm.HISTOGRAM;
 import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_DIFF_SECTION;
 import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_ALGORITHM;
@@ -59,6 +60,7 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
@@ -464,7 +466,7 @@ protected void cleanUp() throws NoWorkTreeException,
 	 * @return the entry which was added to the index
 	 */
 	private DirCacheEntry add(byte[] path, CanonicalTreeParser p, int stage,
-			long lastMod, long len) {
+			Instant lastMod, long len) {
 		if (p != null && !p.getEntryFileMode().equals(FileMode.TREE)) {
 			DirCacheEntry e = new DirCacheEntry(path, stage);
 			e.setFileMode(p.getEntryFileMode());
@@ -491,7 +493,7 @@ private DirCacheEntry keep(DirCacheEntry e) {
 				e.getStage());
 		newEntry.setFileMode(e.getFileMode());
 		newEntry.setObjectId(e.getObjectId());
-		newEntry.setLastModified(e.getLastModified());
+		newEntry.setLastModified(e.getLastModifiedInstant());
 		newEntry.setLength(e.getLength());
 		builder.add(newEntry);
 		return newEntry;
@@ -667,16 +669,17 @@ protected boolean processEntry(CanonicalTreeParser base,
 						// we know about length and lastMod only after we have written the new content.
 						// This will happen later. Set these values to 0 for know.
 						DirCacheEntry e = add(tw.getRawPath(), theirs,
-								DirCacheEntry.STAGE_0, 0, 0);
+								DirCacheEntry.STAGE_0, EPOCH, 0);
 						addToCheckout(tw.getPathString(), e, attributes);
 					}
 					return true;
 				} else {
 					// FileModes are not mergeable. We found a conflict on modes.
 					// For conflicting entries we don't know lastModified and length.
-					add(tw.getRawPath(), base, DirCacheEntry.STAGE_1, 0, 0);
+					add(tw.getRawPath(), base, DirCacheEntry.STAGE_1, EPOCH, 0);
-					add(tw.getRawPath(), ours, DirCacheEntry.STAGE_2, 0, 0);
+					add(tw.getRawPath(), ours, DirCacheEntry.STAGE_2, EPOCH, 0);
-					add(tw.getRawPath(), theirs, DirCacheEntry.STAGE_3, 0, 0);
+					add(tw.getRawPath(), theirs, DirCacheEntry.STAGE_3, EPOCH,
+							0);
 					unmergedPaths.add(tw.getPathString());
 					mergeResults.put(
 							tw.getPathString(),
@@ -708,7 +711,7 @@ protected boolean processEntry(CanonicalTreeParser base,
 				// the new content.
 				// This will happen later. Set these values to 0 for know.
 				DirCacheEntry e = add(tw.getRawPath(), theirs,
-						DirCacheEntry.STAGE_0, 0, 0);
+						DirCacheEntry.STAGE_0, EPOCH, 0);
 				if (e != null) {
 					addToCheckout(tw.getPathString(), e, attributes);
 				}
@@ -737,16 +740,16 @@ protected boolean processEntry(CanonicalTreeParser base,
 			// detected later
 			if (nonTree(modeO) && !nonTree(modeT)) {
 				if (nonTree(modeB))
-					add(tw.getRawPath(), base, DirCacheEntry.STAGE_1, 0, 0);
+					add(tw.getRawPath(), base, DirCacheEntry.STAGE_1, EPOCH, 0);
-				add(tw.getRawPath(), ours, DirCacheEntry.STAGE_2, 0, 0);
+				add(tw.getRawPath(), ours, DirCacheEntry.STAGE_2, EPOCH, 0);
 				unmergedPaths.add(tw.getPathString());
 				enterSubtree = false;
 				return true;
 			}
 			if (nonTree(modeT) && !nonTree(modeO)) {
 				if (nonTree(modeB))
-					add(tw.getRawPath(), base, DirCacheEntry.STAGE_1, 0, 0);
+					add(tw.getRawPath(), base, DirCacheEntry.STAGE_1, EPOCH, 0);
-				add(tw.getRawPath(), theirs, DirCacheEntry.STAGE_3, 0, 0);
+				add(tw.getRawPath(), theirs, DirCacheEntry.STAGE_3, EPOCH, 0);
 				unmergedPaths.add(tw.getPathString());
 				enterSubtree = false;
 				return true;
@@ -773,9 +776,9 @@ protected boolean processEntry(CanonicalTreeParser base,
 			boolean gitlinkConflict = isGitLink(modeO) || isGitLink(modeT);
 			// Don't attempt to resolve submodule link conflicts
 			if (gitlinkConflict || !attributes.canBeContentMerged()) {
-				add(tw.getRawPath(), base, DirCacheEntry.STAGE_1, 0, 0);
+				add(tw.getRawPath(), base, DirCacheEntry.STAGE_1, EPOCH, 0);
-				add(tw.getRawPath(), ours, DirCacheEntry.STAGE_2, 0, 0);
+				add(tw.getRawPath(), ours, DirCacheEntry.STAGE_2, EPOCH, 0);
-				add(tw.getRawPath(), theirs, DirCacheEntry.STAGE_3, 0, 0);
+				add(tw.getRawPath(), theirs, DirCacheEntry.STAGE_3, EPOCH, 0);
 
 				if (gitlinkConflict) {
 					MergeResult<SubmoduleConflict> result = new MergeResult<>(
@@ -822,10 +825,10 @@ protected boolean processEntry(CanonicalTreeParser base,
 				MergeResult<RawText> result = contentMerge(base, ours, theirs,
 						attributes);
 
-				add(tw.getRawPath(), base, DirCacheEntry.STAGE_1, 0, 0);
+				add(tw.getRawPath(), base, DirCacheEntry.STAGE_1, EPOCH, 0);
-				add(tw.getRawPath(), ours, DirCacheEntry.STAGE_2, 0, 0);
+				add(tw.getRawPath(), ours, DirCacheEntry.STAGE_2, EPOCH, 0);
 				DirCacheEntry e = add(tw.getRawPath(), theirs,
-						DirCacheEntry.STAGE_3, 0, 0);
+						DirCacheEntry.STAGE_3, EPOCH, 0);
 
 				// OURS was deleted checkout THEIRS
 				if (modeO == 0) {
@@ -957,9 +960,9 @@ private void updateIndex(CanonicalTreeParser base,
 				// A conflict occurred, the file will contain conflict markers
 				// the index will be populated with the three stages and the
 				// workdir (if used) contains the halfway merged content.
-				add(tw.getRawPath(), base, DirCacheEntry.STAGE_1, 0, 0);
+				add(tw.getRawPath(), base, DirCacheEntry.STAGE_1, EPOCH, 0);
-				add(tw.getRawPath(), ours, DirCacheEntry.STAGE_2, 0, 0);
+				add(tw.getRawPath(), ours, DirCacheEntry.STAGE_2, EPOCH, 0);
-				add(tw.getRawPath(), theirs, DirCacheEntry.STAGE_3, 0, 0);
+				add(tw.getRawPath(), theirs, DirCacheEntry.STAGE_3, EPOCH, 0);
 				mergeResults.put(tw.getPathString(), result);
 				return;
 			}
@@ -976,7 +979,7 @@ private void updateIndex(CanonicalTreeParser base,
 					? FileMode.REGULAR_FILE : FileMode.fromBits(newMode));
 			if (mergedFile != null) {
 				dce.setLastModified(
-						nonNullRepo().getFS().lastModified(mergedFile));
+						nonNullRepo().getFS().lastModifiedInstant(mergedFile));
 				dce.setLength((int) mergedFile.length());
 			}
 			dce.setObjectId(insertMergeResult(rawMerged, attributes));

org.eclipse.jgit/src/org/eclipse/jgit/transport/NetRC.java

@@ -46,6 +46,7 @@
 import java.io.File;
 import java.io.FileReader;
 import java.io.IOException;
+import java.time.Instant;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.Locale;
@@ -123,7 +124,7 @@ boolean complete() {
 
 	private File netrc;
 
-	private long lastModified;
+	private Instant lastModified;
 
 	private Map<String, NetRCEntry> hosts = new HashMap<>();
 
@@ -187,8 +188,10 @@ public NetRCEntry getEntry(String host) {
 		if (netrc == null)
 			return null;
 
-		if (this.lastModified != this.netrc.lastModified())
+		if (!this.lastModified
+				.equals(FS.DETECTED.lastModifiedInstant(this.netrc))) {
 			parse();
+		}
 
 		NetRCEntry entry = this.hosts.get(host);
 
@@ -209,7 +212,7 @@ public Collection<NetRCEntry> getEntries() {
 
 	private void parse() {
 		this.hosts.clear();
-		this.lastModified = this.netrc.lastModified();
+		this.lastModified = FS.DETECTED.lastModifiedInstant(this.netrc);
 
 		try (BufferedReader r = new BufferedReader(new FileReader(netrc))) {
 			String line = null;

org.eclipse.jgit/src/org/eclipse/jgit/transport/OpenSshConfig.java

@@ -51,6 +51,7 @@
 import java.io.InputStreamReader;
 import java.security.AccessController;
 import java.security.PrivilegedAction;
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -166,7 +167,7 @@ public static OpenSshConfig get(FS fs) {
 	private final File configFile;
 
 	/** Modification time of {@link #configFile} when it was last loaded. */
-	private long lastModified;
+	private Instant lastModified;
 
 	/**
 	 * Encapsulates entries read out of the configuration file, and
@@ -224,8 +225,8 @@ public Host lookup(String hostName) {
 	}
 
 	private synchronized State refresh() {
-		final long mtime = configFile.lastModified();
+		final Instant mtime = FS.DETECTED.lastModifiedInstant(configFile);
-		if (mtime != lastModified) {
+		if (!mtime.equals(lastModified)) {
 			State newState = new State();
 			try (FileInputStream in = new FileInputStream(configFile)) {
 				newState.entries = parse(in);

org.eclipse.jgit/src/org/eclipse/jgit/treewalk/FileTreeIterator.java

@@ -53,6 +53,7 @@
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.time.Instant;
 
 import org.eclipse.jgit.dircache.DirCacheIterator;
 import org.eclipse.jgit.errors.IncorrectObjectTypeException;
@@ -406,8 +407,14 @@ public long getLength() {
 		}
 
 		@Override
+		@Deprecated
 		public long getLastModified() {
-			return attributes.getLastModifiedTime();
+			return attributes.getLastModifiedInstant().toEpochMilli();
+		}
+
+		@Override
+		public Instant getLastModifiedInstant() {
+			return attributes.getLastModifiedInstant();
 		}
 
 		@Override

org.eclipse.jgit/src/org/eclipse/jgit/treewalk/WorkingTreeIterator.java

@@ -59,6 +59,7 @@
 import java.nio.charset.CharacterCodingException;
 import java.nio.charset.CharsetEncoder;
 import java.text.MessageFormat;
+import java.time.Instant;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.Comparator;
@@ -645,11 +646,23 @@ public long getEntryContentLength() throws IOException {
 	 *
 	 * @return last modified time of this file, in milliseconds since the epoch
 	 *         (Jan 1, 1970 UTC).
+	 * @deprecated use {@link #getEntryLastModifiedInstant()} instead
 	 */
+	@Deprecated
 	public long getEntryLastModified() {
 		return current().getLastModified();
 	}
 
+	/**
+	 * Get the last modified time of this entry.
+	 *
+	 * @return last modified time of this file
+	 * @since 5.1.9
+	 */
+	public Instant getEntryLastModifiedInstant() {
+		return current().getLastModifiedInstant();
+	}
+
 	/**
 	 * Obtain an input stream to read the file content.
 	 * <p>
@@ -924,30 +937,28 @@ public MetadataDiff compareMetadata(DirCacheEntry entry) {
 
 		// Git under windows only stores seconds so we round the timestamp
 		// Java gives us if it looks like the timestamp in index is seconds
-		// only. Otherwise we compare the timestamp at millisecond precision,
+		// only. Otherwise we compare the timestamp at nanosecond precision,
 		// unless core.checkstat is set to "minimal", in which case we only
 		// compare the whole second part.
-		long cacheLastModified = entry.getLastModified();
+		Instant cacheLastModified = entry.getLastModifiedInstant();
-		long fileLastModified = getEntryLastModified();
+		Instant fileLastModified = getEntryLastModifiedInstant();
-		long lastModifiedMillis = fileLastModified % 1000;
+		if ((getOptions().getCheckStat() == CheckStat.MINIMAL)
-		long cacheMillis = cacheLastModified % 1000;
+				|| (cacheLastModified.getNano() == 0)
-		if (getOptions().getCheckStat() == CheckStat.MINIMAL) {
+				// Some Java version on Linux return whole seconds only even
-			fileLastModified = fileLastModified - lastModifiedMillis;
+				// when the file systems supports more precision.
-			cacheLastModified = cacheLastModified - cacheMillis;
+				|| (fileLastModified.getNano() == 0)) {
-		} else if (cacheMillis == 0)
+			if (fileLastModified.getEpochSecond() != cacheLastModified
-			fileLastModified = fileLastModified - lastModifiedMillis;
+					.getEpochSecond()) {
-		// Some Java version on Linux return whole seconds only even when
+				return MetadataDiff.DIFFER_BY_TIMESTAMP;
-		// the file systems supports more precision.
+			}
-		else if (lastModifiedMillis == 0)
+		}
-			cacheLastModified = cacheLastModified - cacheMillis;
+		if (!fileLastModified.equals(cacheLastModified)) {
-
-		if (fileLastModified != cacheLastModified)
 			return MetadataDiff.DIFFER_BY_TIMESTAMP;
-		else if (!entry.isSmudged())
+		} else if (entry.isSmudged()) {
-			// The file is clean when you look at timestamps.
-			return MetadataDiff.EQUAL;
-		else
 			return MetadataDiff.SMUDGED;
+		}
+		// The file is clean when when comparing timestamps
+		return MetadataDiff.EQUAL;
 	}
 
 	/**
@@ -1274,9 +1285,25 @@ public String toString() {
 		 * instance member instead.
 		 *
 		 * @return time since the epoch (in ms) of the last change.
+		 * @deprecated use {@link #getLastModifiedInstant()} instead
 		 */
+		@Deprecated
 		public abstract long getLastModified();
 
+		/**
+		 * Get the last modified time of this entry.
+		 * <p>
+		 * <b>Note: Efficient implementation required.</b>
+		 * <p>
+		 * The implementation of this method must be efficient. If a subclass
+		 * needs to compute the value they should cache the reference within an
+		 * instance member instead.
+		 *
+		 * @return time of the last change.
+		 * @since 5.1.9
+		 */
+		public abstract Instant getLastModifiedInstant();
+
 		/**
 		 * Get the name of this entry within its directory.
 		 * <p>

org.eclipse.jgit/src/org/eclipse/jgit/util/FS.java

@@ -44,6 +44,7 @@
 package org.eclipse.jgit.util;
 
 import static java.nio.charset.StandardCharsets.UTF_8;
+import static java.time.Instant.EPOCH;
 import static org.eclipse.jgit.lib.Constants.FALLBACK_TIMESTAMP_RESOLUTION;
 
 import java.io.BufferedReader;
@@ -66,6 +67,7 @@
 import java.security.PrivilegedAction;
 import java.text.MessageFormat;
 import java.time.Duration;
+import java.time.Instant;
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.Map;
@@ -625,11 +627,41 @@ public boolean supportsSymlinks() {
 	 * @return last modified time of f
 	 * @throws java.io.IOException
 	 * @since 3.0
+	 * @deprecated use {@link #lastModifiedInstant(Path)} instead
 	 */
+	@Deprecated
 	public long lastModified(File f) throws IOException {
 		return FileUtils.lastModified(f);
 	}
 
+	/**
+	 * Get the last modified time of a file system object. If the OS/JRE support
+	 * symbolic links, the modification time of the link is returned, rather
+	 * than that of the link target.
+	 *
+	 * @param p
+	 *            a {@link Path} object.
+	 * @return last modified time of p
+	 * @since 5.1.9
+	 */
+	public Instant lastModifiedInstant(Path p) {
+		return FileUtils.lastModifiedInstant(p);
+	}
+
+	/**
+	 * Get the last modified time of a file system object. If the OS/JRE support
+	 * symbolic links, the modification time of the link is returned, rather
+	 * than that of the link target.
+	 *
+	 * @param f
+	 *            a {@link File} object.
+	 * @return last modified time of p
+	 * @since 5.1.9
+	 */
+	public Instant lastModifiedInstant(File f) {
+		return FileUtils.lastModifiedInstant(f.toPath());
+	}
+
 	/**
 	 * Set the last modified time of a file system object. If the OS/JRE support
 	 * symbolic links, the link is modified, not the target,
@@ -640,11 +672,28 @@ public long lastModified(File f) throws IOException {
 	 *            last modified time
 	 * @throws java.io.IOException
 	 * @since 3.0
+	 * @deprecated use {@link #setLastModified(Path, Instant)} instead
 	 */
+	@Deprecated
 	public void setLastModified(File f, long time) throws IOException {
 		FileUtils.setLastModified(f, time);
 	}
 
+	/**
+	 * Set the last modified time of a file system object. If the OS/JRE support
+	 * symbolic links, the link is modified, not the target,
+	 *
+	 * @param p
+	 *            a {@link Path} object.
+	 * @param time
+	 *            last modified time
+	 * @throws java.io.IOException
+	 * @since 5.1.9
+	 */
+	public void setLastModified(Path p, Instant time) throws IOException {
+		FileUtils.setLastModified(p, time);
+	}
+
 	/**
 	 * Get the length of a file or link, If the OS/JRE supports symbolic links
 	 * it's the length of the link, else the length of the target.
@@ -1712,9 +1761,19 @@ public long getCreationTime() {
 		/**
 		 * @return the time (milliseconds since 1970-01-01) when this object was
 		 *         last modified
+		 * @deprecated use getLastModifiedInstant instead
 		 */
+		@Deprecated
 		public long getLastModifiedTime() {
-			return lastModifiedTime;
+			return lastModifiedInstant.toEpochMilli();
+		}
+
+		/**
+		 * @return the time when this object was last modified
+		 * @since 5.1.9
+		 */
+		public Instant getLastModifiedInstant() {
+			return lastModifiedInstant;
 		}
 
 		private final boolean isDirectory;
@@ -1725,7 +1784,7 @@ public long getLastModifiedTime() {
 
 		private final long creationTime;
 
-		private final long lastModifiedTime;
+		private final Instant lastModifiedInstant;
 
 		private final boolean isExecutable;
 
@@ -1743,7 +1802,7 @@ public long getLastModifiedTime() {
 		Attributes(FS fs, File file, boolean exists, boolean isDirectory,
 				boolean isExecutable, boolean isSymbolicLink,
 				boolean isRegularFile, long creationTime,
-				long lastModifiedTime, long length) {
+				Instant lastModifiedInstant, long length) {
 			this.fs = fs;
 			this.file = file;
 			this.exists = exists;
@@ -1752,7 +1811,7 @@ public long getLastModifiedTime() {
 			this.isSymbolicLink = isSymbolicLink;
 			this.isRegularFile = isRegularFile;
 			this.creationTime = creationTime;
-			this.lastModifiedTime = lastModifiedTime;
+			this.lastModifiedInstant = lastModifiedInstant;
 			this.length = length;
 		}
 
@@ -1764,7 +1823,7 @@ public long getLastModifiedTime() {
 		 * @param path
 		 */
 		public Attributes(File path, FS fs) {
-			this(fs, path, false, false, false, false, false, 0L, 0L, 0L);
+			this(fs, path, false, false, false, false, false, 0L, EPOCH, 0L);
 		}
 
 		/**
@@ -1810,7 +1869,7 @@ public Attributes getAttributes(File path) {
 		boolean exists = isDirectory || isFile;
 		boolean canExecute = exists && !isDirectory && canExecute(path);
 		boolean isSymlink = false;
-		long lastModified = exists ? path.lastModified() : 0L;
+		Instant lastModified = exists ? lastModifiedInstant(path) : EPOCH;
 		long createTime = 0L;
 		return new Attributes(this, path, exists, isDirectory, canExecute,
 				isSymlink, isFile, createTime, lastModified, -1);

org.eclipse.jgit/src/org/eclipse/jgit/util/FS_Win32.java

@@ -149,7 +149,7 @@ public FileVisitResult visitFile(Path file,
 									attrs.isSymbolicLink(),
 									attrs.isRegularFile(),
 									attrs.creationTime().toMillis(),
-									attrs.lastModifiedTime().toMillis(),
+									attrs.lastModifiedTime().toInstant(),
 									attrs.size());
 							result.add(new FileEntry(f, fs, attributes,
 									fileModeStrategy));

org.eclipse.jgit/src/org/eclipse/jgit/util/FileUtils.java

@@ -76,11 +76,14 @@
 import org.eclipse.jgit.internal.JGitText;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.util.FS.Attributes;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * File Utilities
  */
 public class FileUtils {
+	private static final Logger LOG = LoggerFactory.getLogger(FileUtils.class);
 
 	/**
 	 * Option to delete given {@code File}
@@ -656,12 +659,31 @@ static boolean isSymlink(File file) {
 	 * @return lastModified attribute for given file, not following symbolic
 	 *         links
 	 * @throws IOException
+	 * @deprecated use {@link #lastModifiedInstant(Path)} instead which returns
+	 *             FileTime
 	 */
+	@Deprecated
 	static long lastModified(File file) throws IOException {
 		return Files.getLastModifiedTime(toPath(file), LinkOption.NOFOLLOW_LINKS)
 				.toMillis();
 	}
 
+	/**
+	 * @param path
+	 * @return lastModified attribute for given file, not following symbolic
+	 *         links
+	 */
+	static Instant lastModifiedInstant(Path path) {
+		try {
+			return Files.getLastModifiedTime(path, LinkOption.NOFOLLOW_LINKS)
+					.toInstant();
+		} catch (IOException e) {
+			LOG.error(MessageFormat
+					.format(JGitText.get().readLastModifiedFailed, path));
+			return Instant.ofEpochMilli(path.toFile().lastModified());
+		}
+	}
+
 	/**
 	 * Return all the attributes of a file, without following symbolic links.
 	 *
@@ -680,10 +702,21 @@ static BasicFileAttributes fileAttributes(File file) throws IOException {
 	 * @param time
 	 * @throws IOException
 	 */
+	@Deprecated
 	static void setLastModified(File file, long time) throws IOException {
 		Files.setLastModifiedTime(toPath(file), FileTime.fromMillis(time));
 	}
 
+	/**
+	 * @param path
+	 * @param time
+	 * @throws IOException
+	 */
+	static void setLastModified(Path path, Instant time)
+			throws IOException {
+		Files.setLastModifiedTime(path, FileTime.from(time));
+	}
+
 	/**
 	 * @param file
 	 * @return {@code true} if the given file exists, not following symbolic
@@ -788,7 +821,7 @@ static Attributes getFileAttributesBasic(FS fs, File file) {
 					readAttributes.isSymbolicLink(),
 					readAttributes.isRegularFile(), //
 					readAttributes.creationTime().toMillis(), //
-					readAttributes.lastModifiedTime().toMillis(),
+					readAttributes.lastModifiedTime().toInstant(),
 					readAttributes.isSymbolicLink() ? Constants
 							.encode(readSymLink(file)).length
 							: readAttributes.size());
@@ -827,7 +860,7 @@ public static Attributes getFileAttributesPosix(FS fs, File file) {
 					readAttributes.isSymbolicLink(),
 					readAttributes.isRegularFile(), //
 					readAttributes.creationTime().toMillis(), //
-					readAttributes.lastModifiedTime().toMillis(),
+					readAttributes.lastModifiedTime().toInstant(),
 					readAttributes.size());
 			return attributes;
 		} catch (IOException e) {