RFR: JDK-8164815 - 3 JCK NetworkInterface tests fail on Raspberry Pi

[Mark Sheppard]

Hi,
    please oblige and review the change
http://cr.openjdk.java.net/~msheppar/8164815/webrev/src/java.base/share/classes/java/net/NetworkInterface.java.sdiff.html

to address the issue raised in
https://bugs.openjdk.java.net/browse/JDK-8164815

It was found during testing that, when a system does not have at least one
configured network interface, the Enumeration is instantiated using a 
null value,
which results in an unexpected NPE, when it is used.

this change, adds a specific check of the return value from the getAll() 
native method, and throws
a SocketException should a null value have been returned.

regards
Mark



diff -r 4407b0525631 
src/java.base/share/classes/java/net/NetworkInterface.java
--- a/src/java.base/share/classes/java/net/NetworkInterface.java Tue Nov 
08 16:54:28 2016 -0800
+++ b/src/java.base/share/classes/java/net/NetworkInterface.java Thu Nov 
10 14:43:45 2016 +0000
@@ -335,15 +335,19 @@
       * {@link #getInetAddresses()} to obtain all IP addresses for this 
node
       *
       * @return an Enumeration of NetworkInterfaces found on this machine
-     * @exception  SocketException  if an I/O error occurs.
+     * @exception  SocketException  if an I/O error occurs,
+     *             or if the System does not have at least one configured
+     *             network interface.
       * @see #networkInterfaces()
       */
      public static Enumeration<NetworkInterface> getNetworkInterfaces()
          throws SocketException {
          NetworkInterface[] netifs = getAll();
-        assert netifs != null && netifs.length > 0;
-
+        if (netifs != null && netifs.length > 0) {
          return enumerationFromArray(netifs);
+        } else {
+            throw new SocketException("Platform Configuration problem, 
no network interfaces configured");
+        }
      }

      /**
@@ -361,15 +365,19 @@
       * }</pre>
       *
       * @return a Stream of NetworkInterfaces found on this machine
-     * @exception  SocketException  if an I/O error occurs.
+     * @exception  SocketException  if an I/O error occurs,
+     *             or if the System does not have at least one configured
+     *             network interface.
       * @since 9
       */
      public static Stream<NetworkInterface> networkInterfaces()
          throws SocketException {
          NetworkInterface[] netifs = getAll();
-        assert netifs != null && netifs.length > 0;
-
+        if (netifs != null && netifs.length > 0) {
          return streamFromArray(netifs);
+        }  else {
+            throw new SocketException("Platform Configuration problem, 
no network interfaces configured");
+        }
      }

      private static <T> Enumeration<T> enumerationFromArray(T[] a) {