diff --git a/src/test/org/apache/commons/collections/collection/AbstractTestCollection.java b/src/test/org/apache/commons/collections/collection/AbstractTestCollection.java
index dfde362..00c5d26 100644
--- a/src/test/org/apache/commons/collections/collection/AbstractTestCollection.java
+++ b/src/test/org/apache/commons/collections/collection/AbstractTestCollection.java
@@ -1116,7 +1116,7 @@ public abstract class AbstractTestCollection extends AbstractTestObject {
         verify();
 
         try {
-            array = collection.toArray(null);
+            array = collection.toArray((Object[])null);
             fail("toArray(null) should raise NPE");
         } catch (NullPointerException e) {
             // expected