Extract code/class files from java exe

Hello everyone, before I start I'll state Im a total noob when it comes to hacking or reverse engineering.
I do have experience developing in C,C++,Java C# and some scripting languages (Both in school and at work for several years)

Now, to business
Im trying to make a bot for PokeMMO.
I know the game is written in Java (which is not my strong side), I imported the EXE to eclipse as a reference, and found a lot of classes, looking somewhat obfuscated. (Most of the classes are named A B or OOOOO but I dont know if its actually obfuscated)
I looked at some random classes and I can understand some stuff, like calls to other java libraries, or some strings which are clear.

What Id like to do, is extract .class files from the exe and perhaps even the code if thats possible.

Any tips on how to do so would be appreciated

I attached a pic from eclipse of how the code looks once I open it from the package explorer.
(This is one of the security related functions, as the "SHA1withRSA" string hints.
and I assume its a static function with 2 params.

good luck friends! because me I cannot ...