Hijacking Java Classes

[funkyforumemail () hotmail com]

I have a java .jar, and would like to write the variables being sent to a particular class into a seperate file, then 
continue to execute the class as normal. An example would be a login.class, i would like to intercept the username and 
password going into the class file. The point is that I dont have the original source code, and decompiling and 
recompiling the class is difficult. Replacing the class with my own and somehow resume normal execution seems to be the 
best way.

Please help.

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