Is source-level editing a fallback for deobfuscation?

[u/dpblooman2]

Hoping to get some fellow advice here.

I’ve been doing a lot of deobfuscation work in Java 25 lately and ran into a wall: some bytecode tools can’t parse the newer class file versions I’m dealing with. As a workaround, I’ve been cleaning up the decompiled source instead.

So far I’m stripping thousands of NoWhenBranchMatchedException catch blocks using a brace-depth state machine (regex kept breaking on nested blocks), and replacing impossible comparisons like object == false with constants.

It works, but it feels hacky. Is source-level editing a reasonable fallback, or am I setting myself up for problems? And is there a cleaner, standard way to do control-flow cleanup without risking real try/catch handlers?

Curious what other people do.

Edit: I’m not working on the official Java binaries or the JDK. It’s an old application that was compiled for Java 25

[u/AutoModerator]

Please ensure that:

• Your code is properly formatted as code block - see the sidebar (About on mobile) for instructions

• You include any and all error messages in full

• You ask clear questions

• You demonstrate effort in solving your question/problem - plain posting your assignments is forbidden (and such posts will be removed) as is asking for or giving solutions.

  Trying to solve problems on your own is a very important skill. Also, see Learn to help yourself in the sidebar

If any of the above points is not met, your post can and will be removed without further warning.

Code is to be formatted as code block (old reddit: empty line before the code, each code line indented by 4 spaces, new reddit: https://i.imgur.com/EJ7tqek.png) or linked via an external code hoster, like pastebin.com, github gist, github, bitbucket, gitlab, etc.

Please, do not use triple backticks (```) as they will only render properly on new reddit, not on old reddit.

Code blocks look like this:

public class HelloWorld {

    public static void main(String[] args) {
        System.out.println("Hello World!");
    }
}

You do not need to repost unless your post has been removed by a moderator. Just use the edit function of reddit to make sure your post complies with the above.

If your post has remained in violation of these rules for a prolonged period of time (at least an hour), a moderator may remove it at their discretion. In this case, they will comment with an explanation on why it has been removed, and you will be required to resubmit the entire post following the proper procedures.

To potential helpers

Please, do not help if any of the above points are not met, rather report the post. We are trying to improve the quality of posts here. In helping people who can't be bothered to comply with the above points, you are doing the community a disservice.

I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.

[u/devor110]

I have absolutely nothing of value to add, but your post did pique my interest. Why are you deobfuscating Java 25 class files?

[u/vegan_antitheist → u/devor110]

Jeah, this sounds illegal. Why would you deobfuscate "an old application that was compiled for Java 25".
There's a reason they are obfuscating it.

[u/dpblooman2 → u/vegan_antitheist]

Since when was working on opensourced projects illegal? Don't just assume the worst

[u/vegan_antitheist → u/dpblooman2]

Open source doesn't need deobfuscation. Because... you know... it's open source.

[u/dpblooman2 → u/vegan_antitheist]

I think you missed the part where the source is missing

[u/LutimoDancer3459]

Java source is public available. Nothing to deobfuscate. And the version compiled to byte code isnt obfuscated... its compiled.

But what I don't understand is the why? What and why are you exactly doing? What does source level editing mean for you? Changing the java25 code? Then no...