This is issue has been filed to add better test failure output to jdk/test/java/util/Arrays/ParallelPrefix.java

This test has been seen to fail occasionally on recent JDK 9 builds. It fails with a message similar to:

...
test ParallelPrefix.testParallelPrefixForInt([I@47a7a8ef, 1365, 2730, ParallelPrefix$$Lambda$56/1605520928@106dbc48): success
test ParallelPrefix.testParallelPrefixForInt([I@789e465e, 1365, 2731, ParallelPrefix$$Lambda$55/1326195546@2c8625ae): failure
java.lang.AssertionError: expected [[I@7b703d4a] but found [[I@73625cb4]
at org.testng.Assert.fail(Assert.java:94)
at org.testng.Assert.failNotEquals(Assert.java:494)
at org.testng.Assert.assertArrayEquals(Assert.java:144)
at org.testng.Assert.assertEquals(Assert.java:117)
at org.testng.Assert.assertEquals(Assert.java:165)
at ParallelPrefix.testParallelPrefixForInt(ParallelPrefix.java:124)
…

The output is not very helpful. Testng, or at least the version that we have in use in jtreg, does not provide pretty failure messages when dealing with arrays. It is trivial to add these to the test.