diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/FileReftableStack.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/FileReftableStack.java
index c74a29842..d48a2d726 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/FileReftableStack.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/FileReftableStack.java
@@ -617,6 +617,9 @@ public boolean equals(Object other) {
 			if (other == null) {
 				return false;
 			}
+			if (!(other instanceof Segment)) {
+				return false;
+			}
 			Segment o = (Segment) other;
 			return o.bytes == bytes && o.log == log && o.start == start
 					&& o.end == end;