[9] RFR (M) 8054888: Runtime: Add Diagnostic Command that prints the class hierarchy

[Chris Plummer]

[Hmm. My previous email somehow included the attachment with the dcmd 
output, but not the body of the message, so here it is again.]

Hey Folks,

Sorry about the delay in getting the next webrev for this out. I was 
sidetracked by a few other things, including being out sick of almost a 
week, and there were also quite a few changes to make.

I'm ready for review with an updated webrev, but thought first I'd have 
you look at and comment on the output. Please see the attached file. It 
now supports:

     printing the hierarchy for a single class
     optionally including all subclasses of the specified class (-s)
     for each class, also list all of its interfaces (-i)

The hex value in the output is the address of the ClassLoaderData for 
the ClassLoader of the class. I did not include the address of the 
Klass, but could if you think it would be useful. Changing the format of 
what comes after the classname is easy. Just let me know what you think 
is best.

I have not updated any other dcmds to be consistent with how classes are 
uniquely identified. A separate bug should be filed for that. Actually I 
thought one was, but I looked through this thread's history and could 
not find mention of it. I also have not implemented the reverse 
hierarchy dcmd. JDK-8068830 has already been filed for that, but there 
are no plans to work on it in the near term.

thanks,

Chris