RFR(S): 8228625: [TESTBUG] sun/tools/jhsdb/JShellHeapDumpTest.java fails with RuntimeException 'JShellToolProvider' missing from stdout/stderr

[Chris Plummer]

Hello,

Please review the following changes:

http://cr.openjdk.java.net/~cjplummer/8228625/webrev.00/
https://bugs.openjdk.java.net/browse/JDK-8228625

There are actually numerous ways that JShellHeapDumpTest.java fails. One 
is a test bug, being addressed here, and the rest all seem to be SA 
bugs. Those are now being covered by JDK-8230872. All the issues seem to 
stem from the fact that the test spawns a jshell process, and then 
immediately does a "jhsdb jmap" on the process before jshell has fully 
started up.

The test bug happens when the jmap succeeds, but jshell has not yet 
entered the main java thread. Thus the search for "JShellToolProvider" 
in the output fails. It expects "JShellToolProvider" to be in the output 
because it is part of a method name in the main thread, and the test 
dump all the thread stacks contained in the jmap generated hprof file. 
When the test fails in this way, you can see the stack dump in the 
output, but the main thread is missing.

There's a couple of ways to fix this. One is to just add a delay (10s 
seems to be more than enough), and the other is to retry the "jhsdb 
jmap" command until the stack contains the JShellToolProvider symbol. I 
chose the later because doing a 10s delay masks the SA issues that are 
now covered by JDK-8230872. In a way the 10s delay is a better fix, 
because it makes this test pass every time, but I did not like that it 
also hid real SA problems in JDK-8230872. My plan for now is to do this 
retry fix, and then if there are too many failures due to JDK-8230872, 
then also add a 10s delay, with the intention of removing it once 
JDK-8230872 if fixed. From what I can see, JDK-8230872 failures happen 
on about 1% of the runs.

I made a few of other changes. One was to no longer redirect stderr from 
the jmap process as was done from the following:

processBuilder.redirectError(ProcessBuilder.Redirect.INHERIT);

This causes the output not to appear in the OutputAnalyzer output, 
resulting in the following not working:

             output.shouldNotContain("null");

Also I added code to dump the output of the jshell process so you can 
see if the jshell prompt was ever generated.

thanks,

Chris