Hello guys! I've just started work on a basic 2D Java game (only a player moving around on a screen), which I will be releasing soon along with a text based riddle game.

But, when it came to compiling it into the .jar file, I found that I could easily take the class out of it, and go to a website called ShowMyCode, and basically de-compile the class into the code. At first I thought it was just something I did wrong. Then I took out a class from my Minecraft jar, and it worked to, I could see the source of a Minecraft class.

Are there ways to overcome this to prevent code from being stolen? Because when I start to get good in Java and make some nice software applications with them, how will I prevent my code from being stolen?

Regards,
- Bicentic

Usually you dont have to bother about it. If your game is not the next angry birds, nobody will bother looking at your code. Those who really want to take a look at your code will be able to one way or the other. (Those who are able to do that wont have the need to steal your code anyways).

A simple countermeasure you can take is obfuscation. Not sure if it is available in java, but it basically obfuscates all your classes and members with arbitrary names.



etc.

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Long pork is people!

wzl's burrow

That's just how Minecraft has all their classes laid out. But what if I make I game which gets popular like RuneScape. I know RuneScape is browser based so they don't need to download the jar files etc...

but, I'm not a fan of that. And what if someone finds a part of code to do with money? Then they can create hacks and just ruin the game.

RuneScape is distributed via Jar files. The only difference is that it is done automatically by the browser, but it's trivial finding the cached jar on your hard drive if you want to extract it (a Jar file is just a .zip file with a different extension) and view the code.


You would handle anything important on the server end of the game. That doesn't automatically make things secure of course, but handling important stuff on the client side is more or less an open invitation to cheating/hacking.

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What most people don't understand about "enlightenment" is that it is not an end-goal; but where you find yourself just before taking a new "first step."

Hmm, this idea may seem stupid, and probably wont work but...

What if I make a small C++ application and run the Java in there. And when I compile it I can hide the jar file somehow or have it converted into some file which is un-readable by the computer. I doubt this is possible tho :L

Well, in order to run Java code, you will need to have the standard jar. I suppose you could encrypt that jar and decrypt it at run-time, but that's not going to prevent anything.

Like weezl said, this is more or less a non-issue. But, if you're that worried about someone stealing your code, the best option is to abandon Java altogether and go for a native-compiled language like C++. The only way to get any sort of code security whatsoever is to not use a language that is compiled into bytecode and run by interpreter, and instead opt for native compilation. Note that, even then, it is possible to reverse-engineer software written in *any* language. C++ would do little more than make it more difficult.

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What most people don't understand about "enlightenment" is that it is not an end-goal; but where you find yourself just before taking a new "first step."

A determined reverse engineer....society calls 'em cracker
Neither Bytecode nor Executable distribution is save from the crackers.

Crackers arsenal:
Bytecode > Well they are just easily decompilable...
Executable > They are too though takes time. Eg. IDA

But for Java try ProGuard, how it works is beyond me. But they claim so.

And be afraid masters do it with assembly language

IDA was nice. Haven't been near it for years. Assembler knowledge definitely required.

I did find a C de-compiler years ago. I wrote a "Hello World" console app with Borland Turbo C and ran the resulting .exe through the de-compiler expecting to see reasonable output from a simple program. However, the result was 25 pages of garbage.

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10 PRINT "Bad Monkey ";
20 GOTO 10