Hi there, are there a free tool which can protect .class file and prevent decompiler? And renamed to "a.class", "b.class", "c.class"... Thank you!
Yes, there are some. Those tools are called obfuscators. They change the names of variable, methods, classes so that it becomes difficult to read the code. It also reduces the size of the program (10 to 30% smaller usually).
To use retroguard:
To use proguard: