diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/IndexDiff.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/IndexDiff.java
index f5aaa5e8f..b19e77825 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/IndexDiff.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/IndexDiff.java
@@ -49,6 +49,7 @@ import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashSet;
+import java.util.Set;
 
 import org.eclipse.jgit.dircache.DirCache;
 import org.eclipse.jgit.dircache.DirCacheIterator;
@@ -90,17 +91,17 @@ public class IndexDiff {
 
 	private final WorkingTreeIterator initialWorkingTreeIterator;
 
-	private HashSet<String> added = new HashSet<String>();
+	private Set<String> added = new HashSet<String>();
 
-	private HashSet<String> changed = new HashSet<String>();
+	private Set<String> changed = new HashSet<String>();
 
-	private HashSet<String> removed = new HashSet<String>();
+	private Set<String> removed = new HashSet<String>();
 
-	private HashSet<String> missing = new HashSet<String>();
+	private Set<String> missing = new HashSet<String>();
 
-	private HashSet<String> modified = new HashSet<String>();
+	private Set<String> modified = new HashSet<String>();
 
-	private HashSet<String> untracked = new HashSet<String>();
+	private Set<String> untracked = new HashSet<String>();
 
 	/**
 	 * Construct an IndexDiff
@@ -243,42 +244,42 @@ public class IndexDiff {
 	/**
 	 * @return list of files added to the index, not in the tree
 	 */
-	public HashSet<String> getAdded() {
+	public Set<String> getAdded() {
 		return added;
 	}
 
 	/**
 	 * @return list of files changed from tree to index
 	 */
-	public HashSet<String> getChanged() {
+	public Set<String> getChanged() {
 		return changed;
 	}
 
 	/**
 	 * @return list of files removed from index, but in tree
 	 */
-	public HashSet<String> getRemoved() {
+	public Set<String> getRemoved() {
 		return removed;
 	}
 
 	/**
 	 * @return list of files in index, but not filesystem
 	 */
-	public HashSet<String> getMissing() {
+	public Set<String> getMissing() {
 		return missing;
 	}
 
 	/**
 	 * @return list of files on modified on disk relative to the index
 	 */
-	public HashSet<String> getModified() {
+	public Set<String> getModified() {
 		return modified;
 	}
 
 	/**
 	 * @return list of files on modified on disk relative to the index
 	 */
-	public HashSet<String> getUntracked() {
+	public Set<String> getUntracked() {
 		return untracked;
 	}