Re: Re: rt.jat instrumentation causes JVM crash

Thanks I found it the hard way that java.lang.Thread and java.lang.Object
can't be instrumented.
Thanks,
Guy

On Mon, Oct 19, 2009 at 12:40 PM, Yao Qi <[email protected]> wrote:

> On Sat, Oct 17, 2009 at 2:09 PM, Guy Korland <[email protected]> wrote:
> > Hi,
> >
> > I'm trying to instrument the boot class loader classes, after some
> > long work I found out that adding new field to some of these classes
> > breaks the JVM.
> This topic is NOT related to asm, I think, :)
>
> What "core" classes do you instrument?  It is not supported for JVM
> for instrumented "core" classes, such as java.lang.Thread,
> java.lang.Object.
>
> My preferred approach is to instrument java "core" classes by ASM, and
> dump them in file system as new class files.  Use -Xbootclasspath
> option to replace your original "core" classes.
>
> > So after I removed those fields and left only adding new methods to
> > the boot classes I'm still getting the following error on JVM
> > initialization, any ideas?
> >
> > Error occurred during initialization of VM
> > java.lang.ExceptionInInitializerError
> > Caused by: java.lang.NullPointerException
> >       at java.lang.String.charAt(String.java:689)
> >       at java.security.BasicPermission.init(BasicPermission.java:93)
> >       at java.security.BasicPermission.<init>(BasicPermission.java:129)
> >       at java.lang.RuntimePermission.<init>(RuntimePermission.java:335)
> >       at java.lang.Thread.<clinit>(Thread.java:1493)
> >
> > Or if I don't instrument the java.lang.* classes.
> >
> > Error occurred during initialization of VM
> > java.lang.NullPointerException
> >       at java.util.Hashtable.put(Hashtable.java:394)
> >       at java.lang.System.initProperties(Native Method)
> >       at java.lang.System.initializeSystemClass(System.java:1072)
> >
> > Thanks,
> > Guy
> >
> >
> > --
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> >
>
>
>
> --
> Yao
> GNU/Linux Developer
>
>
> --
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>


-- 
Guy Korland

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