JVM crashes when adding more than 2 methods to java.lang.Object

[Guillaume Pothier]

Hi,
I'm observing a JVM crash when adding public, non-static, non-native
methods to the Object class through instrumentation (either using
JVMTI's ClassFileLoadHook or providing the modified Object class to
the JVM using the -Xbootclasspath/p parameter). Adding one or two
methods causes no problems, but adding more than 2 methods causes the
JVM to crash. I get different kinds of crashes depending on the number
of methods I add. With 3 and 4 methods I get a SIGSEGV; with more
methods I get an NPE during VM initialization (in String.charAt). For
testing purposes, all added
methods take no arguments and return void, and have an empty body
(only the RETURN bytecode).
This occurs with Sun's JDK 1.6_18 and the OpenJDK 1.6_18.
Is that expected behavior? Is there something I can do about it?

Kind regards,
Guillaume Pothier
PhD student, University of Chile