diff --git a/core/src/main/java/org/hibernate/cache/QueryKey.java b/core/src/main/java/org/hibernate/cache/QueryKey.java
index 8bb5a806aa..7d774cad21 100644
--- a/core/src/main/java/org/hibernate/cache/QueryKey.java
+++ b/core/src/main/java/org/hibernate/cache/QueryKey.java
@@ -51,7 +51,8 @@ public class QueryKey implements Serializable {
 	}
 	
 	public boolean equals(Object other) {
-		QueryKey that = (QueryKey) other;
+      if (!(other instanceof QueryKey)) return false;
+      QueryKey that = (QueryKey) other;
 		if ( !sqlQueryString.equals(that.sqlQueryString) ) return false;
 		if ( !EqualsHelper.equals(firstRow, that.firstRow) || !EqualsHelper.equals(maxRows, that.maxRows) ) return false;
 		if ( !EqualsHelper.equals(customTransformer, that.customTransformer) ) return false;