6594296: NetworkInterface.getHardwareAddress returns zero length byte array

Reviewed-by: alanb

src/windows/native/java/net/NetworkInterface_winXP.c

@@ -818,10 +818,12 @@ JNIEXPORT jbyteArray JNICALL Java_java_net_NetworkInterface_getMacAddr0_XP
       ptr = getAdapter(env, index);
       if (ptr != NULL) {
         len = ptr->PhysicalAddressLength;
-        ret = (*env)->NewByteArray(env, len);
-        if (!IS_NULL(ret)) {
-          (*env)->SetByteArrayRegion(env, ret, 0, len,
-                                     (jbyte*) ptr->PhysicalAddress);
+        if (len > 0) {
+          ret = (*env)->NewByteArray(env, len);
+          if (!IS_NULL(ret)) {
+            (*env)->SetByteArrayRegion(env, ret, 0, len,
+                                       (jbyte*) ptr->PhysicalAddress);
+          }
         }
         free(ptr);
       }

test/java/net/NetworkInterface/Test.java

@@ -21,9 +21,9 @@
  * questions.
  */
 
-/* @test 01/02/14
- * @bug 4405354
- * @summary Exercise java.net.NetworkInterface
+/* @test
+ * @bug 4405354 6594296
+ * @summary Basic tests for NetworkInterface
  */
 import java.net.NetworkInterface;
 import java.net.InetAddress;
@@ -69,6 +69,12 @@ public class Test {
                 throw new Exception("hashCode contract broken");
             }
             System.out.println("hashCode() test passed.");
+
+            byte[] ba = ni.getHardwareAddress();
+            if (ba != null && ba.length == 0) {
+                throw new Exception("getHardwareAddress returned 0 length byte array");
+            }
+            System.out.println("getHardwareAddress() test passed.");
         }
 
         // misc tests :-