seeing/editing code in a .jar file

[u/bobbie1165]

im not very good at coding, or anything and i want to see the code in a .jar file and possibly edit it. im not sure if this is the right place, but any help would be appreciated. i did open the code in notepad and it didnt show it correctly, id really appreciate if somebody could maybe attach a link to a simple website where i can easily view code in the file and if possible even edit it

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[u/KillerCodeMonky]

JAR files contain the complied .class files, not Java code. Your options are:

Use a decompiler to turn it back into code. Please note that some metadata and syntax is lost during compilation. More is lost if the vendor used an obfuscator. The code created will be correct, but it may be difficult to read.

Or, you learn to read and write JVM bytecode, which is what will be in the class files.

[u/Living_Fig_6386]

A .jar file doesn't typically contain source code (it can also include it, of course, just that it doesn't typically). The compiled bytecode for the class could be decompiled, but you loose all the comments, structure, and even the variable names that might make it relatively easy to follow. The compiler can so all sorts of things with regard to reordering an restructuring code as it compiles.

You really want the source code, not the compiled bytecode, and that's probably not in the .jar file.

[u/ITCoder]

Use intellij to open it and it will ask you to use its default decompiler. You can select that option. But if code is obfuscated, it might not show much of it

[u/sedj601]

As others have stated, the jar contains .class files. If you want to see those files in the jar, change the file extension to .zip and unzip it. Others have already listed ways to try to get back to .java files.

[u/JGhostThing]

Why? Does your jar contain the source code? This is not normal, but a jar is really just a compressed archive, so theoretically, it could contain anything.

But, by default, java keeps the source code away from the object file.

Now, there are decompilers. I just know they exist, and may not be free. Using them can be a pain, because the variable and method names may not be stored.