diff --git a/solr/solrj/src/test/org/apache/solr/client/solrj/MergeIndexesExampleTestBase.java b/solr/solrj/src/test/org/apache/solr/client/solrj/MergeIndexesExampleTestBase.java
index 147be2817d7..772c868e1eb 100644
--- a/solr/solrj/src/test/org/apache/solr/client/solrj/MergeIndexesExampleTestBase.java
+++ b/solr/solrj/src/test/org/apache/solr/client/solrj/MergeIndexesExampleTestBase.java
@@ -59,6 +59,7 @@ public abstract class MergeIndexesExampleTestBase extends SolrExampleTestBase {
   @AfterClass
   public static void afterClass() {
     cores.shutdown();
+    cores = null;
   }
   
   @Override