--- a/test/java/net/NetworkInterface/IndexTest.java	Tue Aug 06 14:04:49 2013 +0400
+++ b/test/java/net/NetworkInterface/IndexTest.java	Tue Aug 06 15:35:20 2013 +0100
@@ -27,7 +27,10 @@
  */
 
 import java.net.*;
+import java.util.Arrays;
+import java.util.Collections;
 import java.util.Enumeration;
+import static java.lang.System.out;
 
 public class IndexTest {
     public static void main(String[] args) throws Exception {
@@ -39,12 +42,17 @@
             if (index >= 0) {
                 NetworkInterface nif2 = NetworkInterface.getByIndex(index);
                 if (! nif.equals(nif2)) {
+                    out.printf("%nExpected interfaces to be the same, but got:%n");
+                    displayInterfaceInformation(nif);
+                    displayInterfaceInformation(nif2);
                     throw new RuntimeException("both interfaces should be equal");
                 }
             }
         }
         try {
             nif = NetworkInterface.getByIndex(-1);
+            out.printf("%ngetByIndex(-1) should have thrown, but instead returned:%n");
+            displayInterfaceInformation(nif);
             throw new RuntimeException("Should have thrown IllegalArgumentException");
         } catch (IllegalArgumentException e) {
             // OK
@@ -52,7 +60,29 @@
         // In all likelyhood, this interface should not exist.
         nif = NetworkInterface.getByIndex(Integer.MAX_VALUE - 1);
         if (nif != null) {
+            out.printf("%ngetByIndex(MAX_VALUE - 1), expected null, got:%n");
+            displayInterfaceInformation(nif);
             throw new RuntimeException("getByIndex() should have returned null");
         }
     }
+
+    static void displayInterfaceInformation(NetworkInterface netint) throws SocketException {
+        out.printf("Display name: %s%n", netint.getDisplayName());
+        out.printf("Name: %s%n", netint.getName());
+        Enumeration<InetAddress> inetAddresses = netint.getInetAddresses();
+
+        for (InetAddress inetAddress : Collections.list(inetAddresses))
+            out.printf("InetAddress: %s%n", inetAddress);
+
+        out.printf("Up? %s%n", netint.isUp());
+        out.printf("Loopback? %s%n", netint.isLoopback());
+        out.printf("PointToPoint? %s%n", netint.isPointToPoint());
+        out.printf("Supports multicast? %s%n", netint.supportsMulticast());
+        out.printf("Virtual? %s%n", netint.isVirtual());
+        out.printf("Hardware address: %s%n",
+                    Arrays.toString(netint.getHardwareAddress()));
+        out.printf("MTU: %s%n", netint.getMTU());
+        out.printf("Index: %s%n", netint.getIndex());
+        out.printf("%n");
+     }
 }