diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/dircache/DirCacheIteratorTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/dircache/DirCacheIteratorTest.java
index af1c8a356..dd242e5a1 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/dircache/DirCacheIteratorTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/dircache/DirCacheIteratorTest.java
@@ -76,9 +76,10 @@ public void testEmptyTree_WithTreeWalk() throws Exception {
 		final DirCache dc = DirCache.newInCore();
 		assertEquals(0, dc.getEntryCount());
 
-		final TreeWalk tw = new TreeWalk(db);
-		tw.addTree(new DirCacheIterator(dc));
-		assertFalse(tw.next());
+		try (final TreeWalk tw = new TreeWalk(db)) {
+			tw.addTree(new DirCacheIterator(dc));
+			assertFalse(tw.next());
+		}
 	}
 
 	@Test
@@ -125,19 +126,20 @@ public void testNoSubtree_WithTreeWalk() throws Exception {
 		b.finish();
 
 		final DirCacheIterator i = new DirCacheIterator(dc);
-		final TreeWalk tw = new TreeWalk(db);
-		tw.addTree(i);
-		int pathIdx = 0;
-		while (tw.next()) {
-			assertSame(i, tw.getTree(0, DirCacheIterator.class));
-			assertEquals(pathIdx, i.ptr);
-			assertSame(ents[pathIdx], i.getDirCacheEntry());
-			assertEquals(paths[pathIdx], tw.getPathString());
-			assertEquals(modes[pathIdx].getBits(), tw.getRawMode(0));
-			assertSame(modes[pathIdx], tw.getFileMode(0));
-			pathIdx++;
+		try (final TreeWalk tw = new TreeWalk(db)) {
+			tw.addTree(i);
+			int pathIdx = 0;
+			while (tw.next()) {
+				assertSame(i, tw.getTree(0, DirCacheIterator.class));
+				assertEquals(pathIdx, i.ptr);
+				assertSame(ents[pathIdx], i.getDirCacheEntry());
+				assertEquals(paths[pathIdx], tw.getPathString());
+				assertEquals(modes[pathIdx].getBits(), tw.getRawMode(0));
+				assertSame(modes[pathIdx], tw.getFileMode(0));
+				pathIdx++;
+			}
+			assertEquals(paths.length, pathIdx);
 		}
-		assertEquals(paths.length, pathIdx);
 	}
 
 	@Test
@@ -162,26 +164,27 @@ public void testSingleSubtree_NoRecursion() throws Exception {
 		final int expPos[] = { 0, -1, 4 };
 
 		final DirCacheIterator i = new DirCacheIterator(dc);
-		final TreeWalk tw = new TreeWalk(db);
-		tw.addTree(i);
-		tw.setRecursive(false);
-		int pathIdx = 0;
-		while (tw.next()) {
-			assertSame(i, tw.getTree(0, DirCacheIterator.class));
-			assertEquals(expModes[pathIdx].getBits(), tw.getRawMode(0));
-			assertSame(expModes[pathIdx], tw.getFileMode(0));
-			assertEquals(expPaths[pathIdx], tw.getPathString());
+		try (final TreeWalk tw = new TreeWalk(db)) {
+			tw.addTree(i);
+			tw.setRecursive(false);
+			int pathIdx = 0;
+			while (tw.next()) {
+				assertSame(i, tw.getTree(0, DirCacheIterator.class));
+				assertEquals(expModes[pathIdx].getBits(), tw.getRawMode(0));
+				assertSame(expModes[pathIdx], tw.getFileMode(0));
+				assertEquals(expPaths[pathIdx], tw.getPathString());
 
-			if (expPos[pathIdx] >= 0) {
-				assertEquals(expPos[pathIdx], i.ptr);
-				assertSame(ents[expPos[pathIdx]], i.getDirCacheEntry());
-			} else {
-				assertSame(FileMode.TREE, tw.getFileMode(0));
+				if (expPos[pathIdx] >= 0) {
+					assertEquals(expPos[pathIdx], i.ptr);
+					assertSame(ents[expPos[pathIdx]], i.getDirCacheEntry());
+				} else {
+					assertSame(FileMode.TREE, tw.getFileMode(0));
+				}
+
+				pathIdx++;
 			}
-
-			pathIdx++;
+			assertEquals(expPaths.length, pathIdx);
 		}
-		assertEquals(expPaths.length, pathIdx);
 	}
 
 	@Test
@@ -202,21 +205,22 @@ public void testSingleSubtree_Recursive() throws Exception {
 		b.finish();
 
 		final DirCacheIterator i = new DirCacheIterator(dc);
-		final TreeWalk tw = new TreeWalk(db);
-		tw.addTree(i);
-		tw.setRecursive(true);
-		int pathIdx = 0;
-		while (tw.next()) {
-			final DirCacheIterator c = tw.getTree(0, DirCacheIterator.class);
-			assertNotNull(c);
-			assertEquals(pathIdx, c.ptr);
-			assertSame(ents[pathIdx], c.getDirCacheEntry());
-			assertEquals(paths[pathIdx], tw.getPathString());
-			assertEquals(mode.getBits(), tw.getRawMode(0));
-			assertSame(mode, tw.getFileMode(0));
-			pathIdx++;
+		try (final TreeWalk tw = new TreeWalk(db)) {
+			tw.addTree(i);
+			tw.setRecursive(true);
+			int pathIdx = 0;
+			while (tw.next()) {
+				final DirCacheIterator c = tw.getTree(0, DirCacheIterator.class);
+				assertNotNull(c);
+				assertEquals(pathIdx, c.ptr);
+				assertSame(ents[pathIdx], c.getDirCacheEntry());
+				assertEquals(paths[pathIdx], tw.getPathString());
+				assertEquals(mode.getBits(), tw.getRawMode(0));
+				assertSame(mode, tw.getFileMode(0));
+				pathIdx++;
+			}
+			assertEquals(paths.length, pathIdx);
 		}
-		assertEquals(paths.length, pathIdx);
 	}
 
 	@Test
@@ -236,21 +240,22 @@ public void testTwoLevelSubtree_Recursive() throws Exception {
 			b.add(ents[i]);
 		b.finish();
 
-		final TreeWalk tw = new TreeWalk(db);
-		tw.addTree(new DirCacheIterator(dc));
-		tw.setRecursive(true);
-		int pathIdx = 0;
-		while (tw.next()) {
-			final DirCacheIterator c = tw.getTree(0, DirCacheIterator.class);
-			assertNotNull(c);
-			assertEquals(pathIdx, c.ptr);
-			assertSame(ents[pathIdx], c.getDirCacheEntry());
-			assertEquals(paths[pathIdx], tw.getPathString());
-			assertEquals(mode.getBits(), tw.getRawMode(0));
-			assertSame(mode, tw.getFileMode(0));
-			pathIdx++;
+		try (final TreeWalk tw = new TreeWalk(db)) {
+			tw.addTree(new DirCacheIterator(dc));
+			tw.setRecursive(true);
+			int pathIdx = 0;
+			while (tw.next()) {
+				final DirCacheIterator c = tw.getTree(0, DirCacheIterator.class);
+				assertNotNull(c);
+				assertEquals(pathIdx, c.ptr);
+				assertSame(ents[pathIdx], c.getDirCacheEntry());
+				assertEquals(paths[pathIdx], tw.getPathString());
+				assertEquals(mode.getBits(), tw.getRawMode(0));
+				assertSame(mode, tw.getFileMode(0));
+				pathIdx++;
+			}
+			assertEquals(paths.length, pathIdx);
 		}
-		assertEquals(paths.length, pathIdx);
 	}
 
 	@Test
@@ -397,22 +402,23 @@ public void testTwoLevelSubtree_FilterPath() throws Exception {
 			b.add(ents[i]);
 		b.finish();
 
-		final TreeWalk tw = new TreeWalk(db);
-		for (int victimIdx = 0; victimIdx < paths.length; victimIdx++) {
-			tw.reset();
-			tw.addTree(new DirCacheIterator(dc));
-			tw.setFilter(PathFilterGroup.createFromStrings(Collections
-					.singleton(paths[victimIdx])));
-			tw.setRecursive(tw.getFilter().shouldBeRecursive());
-			assertTrue(tw.next());
-			final DirCacheIterator c = tw.getTree(0, DirCacheIterator.class);
-			assertNotNull(c);
-			assertEquals(victimIdx, c.ptr);
-			assertSame(ents[victimIdx], c.getDirCacheEntry());
-			assertEquals(paths[victimIdx], tw.getPathString());
-			assertEquals(mode.getBits(), tw.getRawMode(0));
-			assertSame(mode, tw.getFileMode(0));
-			assertFalse(tw.next());
+		try (final TreeWalk tw = new TreeWalk(db)) {
+			for (int victimIdx = 0; victimIdx < paths.length; victimIdx++) {
+				tw.reset();
+				tw.addTree(new DirCacheIterator(dc));
+				tw.setFilter(PathFilterGroup.createFromStrings(Collections
+						.singleton(paths[victimIdx])));
+				tw.setRecursive(tw.getFilter().shouldBeRecursive());
+				assertTrue(tw.next());
+				final DirCacheIterator c = tw.getTree(0, DirCacheIterator.class);
+				assertNotNull(c);
+				assertEquals(victimIdx, c.ptr);
+				assertSame(ents[victimIdx], c.getDirCacheEntry());
+				assertEquals(paths[victimIdx], tw.getPathString());
+				assertEquals(mode.getBits(), tw.getRawMode(0));
+				assertSame(mode, tw.getFileMode(0));
+				assertFalse(tw.next());
+			}
 		}
 	}
 
@@ -424,18 +430,19 @@ public void testRemovedSubtree() throws Exception {
 		final DirCache dc = DirCache.read(path, FS.DETECTED);
 		assertEquals(2, dc.getEntryCount());
 
-		final TreeWalk tw = new TreeWalk(db);
-		tw.setRecursive(true);
-		tw.addTree(new DirCacheIterator(dc));
+		try (final TreeWalk tw = new TreeWalk(db)) {
+			tw.setRecursive(true);
+			tw.addTree(new DirCacheIterator(dc));
 
-		assertTrue(tw.next());
-		assertEquals("a/a", tw.getPathString());
-		assertSame(FileMode.REGULAR_FILE, tw.getFileMode(0));
+			assertTrue(tw.next());
+			assertEquals("a/a", tw.getPathString());
+			assertSame(FileMode.REGULAR_FILE, tw.getFileMode(0));
 
-		assertTrue(tw.next());
-		assertEquals("q", tw.getPathString());
-		assertSame(FileMode.REGULAR_FILE, tw.getFileMode(0));
+			assertTrue(tw.next());
+			assertEquals("q", tw.getPathString());
+			assertSame(FileMode.REGULAR_FILE, tw.getFileMode(0));
 
-		assertFalse(tw.next());
+			assertFalse(tw.next());
+		}
 	}
 }