diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/InMemoryRepository.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/InMemoryRepository.java
index 5a8207ed0..583b8b3f6 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/InMemoryRepository.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/InMemoryRepository.java
@@ -66,7 +66,16 @@ public InMemoryRepository(DfsRepositoryDescription repoDesc) {
 	InMemoryRepository(Builder builder) {
 		super(builder);
 		objdb = new MemObjDatabase(this);
-		refdb = new MemRefDatabase();
+		refdb = createRefDatabase();
+	}
+
+	/**
+	 * Creates a new in-memory ref database.
+	 *
+	 * @return a new in-memory reference database.
+	 */
+	protected MemRefDatabase createRefDatabase() {
+		return new MemRefDatabase();
 	}
 
 	/** {@inheritDoc} */