RFR 8023090: Additional debug info for java/net/NetworkInterface/Equals.java

[Chris Hegarty]

Another NetworkInterface test failed for an unexplainable reason, and is 
not readily reproducible on the same machine. Similar to IndexTest.java 
I would like to add some additional diagnostic information so we can try 
to determine the cause of the failure, if seen again.

Additionaly, this test captures all the network interface configuration 
and displays it, along with the failure, only if the test fails. There 
are no functional changes to the test itself.

diff -r bca19fdd875a test/java/net/NetworkInterface/Equals.java
--- a/test/java/net/NetworkInterface/Equals.java        Tue Aug 13 
13:04:21 2013 +0400
+++ b/test/java/net/NetworkInterface/Equals.java        Thu Aug 15 
10:38:17 2013 +0100
@@ -25,41 +25,82 @@
   * @bug 7003398
   * @run main/othervm Equals
   */
+
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+import java.net.InetAddress;
  import java.net.NetworkInterface;
-import java.net.InetAddress;
+import java.net.SocketException;
+import java.util.Arrays;
+import java.util.Collections;
  import java.util.Enumeration;
  import java.util.HashMap;

  public class Equals {

      public static void main(String args[]) throws Exception {
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        PrintStream bufferedOut = new PrintStream(baos);

-        Enumeration nifs1 = NetworkInterface.getNetworkInterfaces();
+        Enumeration<NetworkInterface> nifs1 = 
NetworkInterface.getNetworkInterfaces();
          HashMap<String,Integer> hashes = new HashMap<>();
          HashMap<String,NetworkInterface> nicMap = new HashMap<>();

          while (nifs1.hasMoreElements()) {
-            NetworkInterface ni = (NetworkInterface)nifs1.nextElement();
+            NetworkInterface ni = nifs1.nextElement();
              hashes.put(ni.getName(),ni.hashCode());
              nicMap.put(ni.getName(),ni);
+            displayInterfaceInformation(ni, bufferedOut);
+            bufferedOut.flush();
          }

          System.setSecurityManager(new SecurityManager());

-        Enumeration nifs2 = NetworkInterface.getNetworkInterfaces();
+        Enumeration<NetworkInterface> nifs2 = 
NetworkInterface.getNetworkInterfaces();
          while (nifs2.hasMoreElements()) {
-            NetworkInterface ni = (NetworkInterface)nifs2.nextElement();
+            NetworkInterface ni = nifs2.nextElement();
              NetworkInterface niOrig = nicMap.get(ni.getName());

-            int h = hashes.get(ni.getName());
-            if (h != ni.hashCode()) {
+            int h = ni.hashCode();
+            if (h == hashes.get(ni.getName())) {
+                System.out.printf("%nSystem information:%n");
+                System.out.printf("%s", baos.toString("UTF8"));
+                System.out.printf("%nni.hashCode() returned %d, 
expected %d, for:%n",
+                                  h, hashes.get(ni.getName()));
+                displayInterfaceInformation(ni,System.out);
                  throw new RuntimeException ("Hashcodes different for " +
                          ni.getName());
              }
              if (!ni.equals(niOrig)) {
+                System.out.printf("%nSystem information:%n");
+                System.out.printf("%s", baos.toString("UTF8"));
+                System.out.printf("%nExpected the following interfaces 
to be the same:%n");
+                displayInterfaceInformation(niOrig, System.out);
+                displayInterfaceInformation(ni,System.out);
                  throw new RuntimeException ("equality different for " +
                          ni.getName());
              }
          }
      }
+
+    static void displayInterfaceInformation(NetworkInterface netint,
+                                            PrintStream out) 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");
+     }
  }

-Chris.