class file decompilation.

[dmjpro]

Few days ago I tried to decompile a class file which generates some JVM instructions. It is not generating the original code. Actually i got that class file from a jar file. Now my question is that what causes that happen.
I mean what is way of building a class file so that after decompilation the original code doesn't get generated.
And what is way to get the original code of dis such situation.

[r035198x]

Google for "Obfuscation".

[JosAH]

Few days ago I tried to decompile a class file which generates some JVM instructions. It is not generating the original code. Actually i got that class file from a jar file. Now my question is that what causes that happen.
I mean what is way of building a class file so that after decompilation the original code doesn't get generated.
And what is way to get the original code of dis such situation.

It doesn't matter where the class came from, i.e. it can be a file or it can be an
entry in a .jar file or whatever. If you have used javap: it can't decompile anything
to its original code, it can only disassemble the generated byte code (machine
code). The process of compiling something from source code to byte code is
not a bijective operation so almost never the original source code comes up after
decompilation. If you want the source file to be more or less unreadable check
the previous reply and use obfuscation.

kind regards,

Jos

[dmjpro]

It doesn't matter where the class came from, i.e. it can be a file or it can be an
entry in a .jar file or whatever. If you have used javap: it can't decompile anything
to its original code, it can only disassemble the generated byte code (machine
code). The process of compiling something from source code to byte code is
not a bijective operation so almost never the original source code comes up after
decompilation. If you want the source file to be more or less unreadable check
the previous reply and use obfuscation.

kind regards,

Jos

Thanks Josh!
It proved very useful to me.
No no I used first cavaj then i used jad in both case i got same result.