make AntClassLoader$ResourceEnumeration adhere to the Enumeration contract. PR 51579

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@1155197 13f79535-47bb-0310-9956-ffa450edef68

WHATSNEW

@@ -4,6 +4,12 @@ Changes from Ant 1.8.2 TO Ant 1.8.3
 Changes that could break older environments:
 -------------------------------------------
 
+ * The Enumeration returned by AntClassLoader#getResources used to
+   return null in nextElement after hasNextElement would return false.
+   It has been changed to throw a NoSuchElementException instead so
+   that it now adheres to the contract of java.util.Enumeration.
+   Bugzilla Report 51579.
+
 Fixed bugs:
 -----------
 

src/main/org/apache/tools/ant/AntClassLoader.java

@@ -33,6 +33,7 @@ import java.util.Enumeration;
 import java.util.HashMap;
 import java.util.Hashtable;
 import java.util.Map;
+import java.util.NoSuchElementException;
 import java.util.StringTokenizer;
 import java.util.Vector;
 import java.util.jar.Attributes;
@@ -127,6 +128,9 @@ public class AntClassLoader extends ClassLoader implements SubBuildListener {
          */
         public Object nextElement() {
             URL ret = this.nextResource;
+            if (ret == null) {
+                throw new NoSuchElementException();
+            }
             findNextResource();
             return ret;
         }