some puzzles about Openjdk

[Dalibor Topic]

Liu lianshun wrote:
> Firstly, I want to know that whether I can change the java programes'
> behavior via changing some source files in OpenJDK, for examples,
> execute the following codes will print "100".
>     int i=100;
>     System.out.println(i);
> My question is that how to print "200", without changing the source
> codes. Is it possible?

Is it possible to change behavior of programs by changing the 
source code of OpenJDK? Yes. You can make them all crash 
very fast by doing something bad in the VM for example. ;)

Is it possible to change behavior of programs without changing the 
source code of OpenJDK? Yes, check out aspect oriented programming 
using, for example, AspectJ.

> Secondly, the number of files in the OpenJDK project is very large, I
> want to know how these files are structured. Besides, how can I debug
> the project? 

Volker Simonis wrote a couple of blog entries on how to get started hacking 
on the VM, starting with:

http://weblogs.java.net/blog/simonis/archive/2008/01/hotspot_develop.html

have fun!

dalibor topic

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