RFR JDK-8170114 jimage extract to not an empty directory overwrites content of the directory

[mandy chung]

On 2/9/18 7:23 AM, Michal Vala wrote:
>
> Patch validates output directory before any jimage extracting happen. 
> I've moved validation to extra private method as it is few lines of 
> code. I've also added proper error message for case when output path 
> is not a directory (JImageTask.java#449).
>

Thanks for looking at JDK-8170114 and JDK-8170120.  I took a look at  
http://cr.openjdk.java.net/~shade/8170114/webrev.01/

Alternatively,  jimage extract can behave as jlink and it fails if the 
specified output directory exists including empty directory. It'd be 
easy to delete the directory in the command-line before running jimage.

You extend JImageCliTest to handle the beforeTest method to be invoked 
before running each test case.  Is that necessary?  The test itself is 
creating temp file/directory for each test case.    I think it'd be good 
to update the test to create a named file/dir under the scratch area as 
jtreg will take care of cleaning the scratch area.

Mandy