I've been playing around with decompiling Android apps from dex/jar files to java source code, with varying success. I've tried the usual suspects - JD-GUI, procyon, cfr, krakatau and jadx. I'm having a specific problem with all of them on a particular app in that it's obfuscated, and many classes seem to be split up into multiple files. AFAIK, this isn't allowed in Java.
Also, the classes seem to extends multiple base classes, e.g. class a extends Activity, and class a(or renamed to something else but I know is actually class a as it tries to access a's private member variables directly) extends BroadcastReceiver. AFAIK, this isn't allowed in Java either.
As a result, the decompiled code is full of errors and hard to follow. I'm not expecting a compileable code form the decompiled code, but I do wish to at least be able to perform meaningful static analysis, which is hard to do when the decompiled source doesn't follow java conventions.
Any help on how to resolve this decompilation issue?