This week's giveaway is in the EJB and other Java EE Technologies forum. We're giving away four copies of EJB 3 in Action and have Debu Panda, Reza Rahman, Ryan Cuprak, and Michael Remijan on-line! See this thread for details.
after some tests, here are my results if no code obfuscators is used, the name of instance variables, static variables, method can be obtained by decompilation of the byte-code. The only thing taht's lost is the local variable name(and so method parameters names as well)