Protect the code?

[joaogl]

Hello, there is any way to protect the code? I mean with the .jar file we can get the classes and change them there is any way to protect them from being changed?

[princec]

You can obfuscate them (google Proguard) which makes it a bit harder, and encrypt the jar file and load it with a custom classloader which makes it even more inconvenient temporarily, but that's about it.

Cas

[Roquen]

Short answer: no. 

Longer answer: You can do some work which will prevent most people.  Or a lot of work which will prevent an ever smaller number of people for the amount of effort you put into it.  But ultimately, regardless of how much work you do, the answer is: (SEE: short answer above).

Games published by our own members! Check 'em out!

[GabrielBailey74]

Somebody can download:
http://www.softpedia.com/get/Programming/Debuggers-Decompilers-Dissasemblers/JAD.shtml
and have your code decompiled (Translated from .class files to .java files) within a few seconds .

[Best Username Ever]

You can't do it. You can make it more difficult. Many of the ways you can do that are the same techniques viruses use to hide themselves. Some big companies also install "anti cheat" or licensing programs, which behave a lot like viruses, too.

Keep in mind that even protected native binary executable files are easy to change.

[GabrielBailey74]

I do believe it's possible to 'Plug In' to a running Java process.
In example: Intercept / Manipulate data of the program/process.

Lol, my example is of the game 'Rune Scape' (Programmed in Java).

If somebody were to download and run:
http://cheatengine.org/
They would be able to 'Plug In' to almost any running process on their computer and manipulate it to their likings.

In example: If your game has a variable for 'Gold' they would be able to attach the 'Cheat Engine' to your Game (Java Process), scan and view all the values of the variables in the game, they could than find the current value for the gold, and change the value of it to whatever they want.

Hope the above makes sense.