diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/FileRepository.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/FileRepository.java
index a2daef30d..c8d3ffcd8 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/FileRepository.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/FileRepository.java
@@ -21,6 +21,7 @@
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
+import java.nio.file.Files;
 import java.text.MessageFormat;
 import java.text.ParseException;
 import java.util.ArrayList;
@@ -727,7 +728,8 @@ void convertToReftable(boolean writeLogs, boolean backup)
 			throws IOException {
 		File reftableDir = new File(getDirectory(), Constants.REFTABLE);
 		File headFile = new File(getDirectory(), Constants.HEAD);
-		if (reftableDir.exists() && reftableDir.listFiles().length > 0) {
+		if (reftableDir.exists()
+				&& Files.list(reftableDir.toPath()).findAny().isPresent()) {
 			throw new IOException(JGitText.get().reftableDirExists);
 		}