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

Edit2: Found help in another programming sub that suggested parsing the bytecode with a current library (java.lang.classfile in JDK 24+), and using JavaParser instead of regex for cleanup. Not sure why everyone here was so difficult and rude. Nobody here wanted to actually talk. Marking solved.

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[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/dpblooman2 → u/devor110]

Mostly curiosity about whether an abandoned project is still salvageable for personal use. It was originally open-sourced, but the author deleted their repo.

[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/a-boy-2]

wholesome chungus 100 + reddit gold

[u/TW-Twisti]

Why would an abandoned, previously open source project that had its repo deleted be obfuscated ? That story just makes no sense at all. The dev decided to abandon the project, but first put in the work to obfuscate it, while it was still available as source, only to then abandon it ?

[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...

[u/dpblooman2 → u/LutimoDancer3459]

The original repo got deleted, so I only have bytecode. My tools can’t parse Java 25 class files, so I’m working from decompiled output instead. I’m not changing the Java 25 code. I’m cleaning up artifacts from the decompiler... It's an abandonware project for myself. Mostly learning.