diff --git a/openjpa-kernel/src/main/java/org/apache/openjpa/util/BlacklistClassResolver.java b/openjpa-kernel/src/main/java/org/apache/openjpa/util/BlacklistClassResolver.java
index 799225502..e48e578e1 100644
--- a/openjpa-kernel/src/main/java/org/apache/openjpa/util/BlacklistClassResolver.java
+++ b/openjpa-kernel/src/main/java/org/apache/openjpa/util/BlacklistClassResolver.java
@@ -20,10 +20,9 @@ package org.apache.openjpa.util;
 
 public class BlacklistClassResolver {
     public static final BlacklistClassResolver DEFAULT = new BlacklistClassResolver(
-        toArray(
-            System.getProperty(
-                "openjpa.serialization.class.blacklist",
-                "org.codehaus.groovy.runtime.,org.apache.commons.collections.functors.,org.apache.xalan")),
+        toArray(System.getProperty(
+            "openjpa.serialization.class.blacklist",
+            "org.codehaus.groovy.runtime.,org.apache.commons.collections.functors.,org.apache.xalan")),
         toArray(System.getProperty("openjpa.serialization.class.whitelist")));
 
     private final String[] blacklist;
@@ -35,7 +34,7 @@ public class BlacklistClassResolver {
     }
 
     protected boolean isBlacklisted(final String name) {
-        return !contains(whitelist, name) && contains(blacklist, name);
+        return (whitelist != null && !contains(whitelist, name)) || contains(blacklist, name);
     }
 
     public final String check(final String name) {