Review request for 6858708: HotspotDiagnosticMXBean.setVMOption() throws NullPointerException

[Tomas Hurka]

Hi All,

The NullPointerException is thrown only if the setVMOption() is  
invoked for HeapDumpPath VM option. Due to CR 6604006, default value  
for HeapDumpPath flag is now null (instead of an empty string) and  
therefor flag.getValue() in HotSpotDiagnostic.setVMOption() now  
returns null. This causes that the type of flag is not recognized and  
error-reporting code in setVMOption() throws NPE.

Webrev at:
    http://cr.openjdk.java.net/~thurka/6858708/webrev.01/

The fix is simple - convert null to empty string in the  
sun.management.Flag constructor. This way type of the flag is  
recognized as String. I also added test.
In general it is not very nice that sun.management.Flag uses value of  
the flag to detect its type so maybe whole code should be rewritten to  
explicitly specify type of the flag.

Thanks,
--
Tomas Hurka   <mailto:tomas.hurka at sun.com>
NetBeans Profiler http://profiler.netbeans.org
VisualVM http://visualvm.dev.java.net
Software Engineer, Developer Platforms Group
Sun Microsystems, Praha Czech Republic