diff --git a/vtm/src/org/oscim/theme/MatchingCacheKey.java b/vtm/src/org/oscim/theme/MatchingCacheKey.java
index d2c53fbc..8d79f493 100644
--- a/vtm/src/org/oscim/theme/MatchingCacheKey.java
+++ b/vtm/src/org/oscim/theme/MatchingCacheKey.java
@@ -63,6 +63,9 @@ class MatchingCacheKey {
 
 	@Override
 	public boolean equals(Object obj) {
+		if (obj == null)
+			return false;
+
 		if (this == obj)
 			return true;