RFR for bug JDK-8035633 TEST_BUG: java/net/NetworkInterface/Equals.java and some tests failed on windows intermittently

[Eric Wang]

Hi Everyone,

I'm working on the test bug 
https://bugs.openjdk.java.net/browse/JDK-8035633, There are 4 tests (one 
is in a closed test) failed due to NullPointerException.
All tests failed at similar places "if (isWindows && 
ni.getDisplayName().contains("Teredo"))", the root cause is the 
NetworkInterface may return null if no display name is available.
so the fix is to make sure the display name is not null before calling 
the method "contains("Teredo")", something like "if (isWindows && 
displayName != null && displayName.contains("Teredo"))"

Please let me know if you have any comment. The webrev will be sent 
after internal review.

Thanks,
Eric