Java Decompiler

NerfNerder

Anybody know a good java decompiler that actually works? I've tried a few I found on google but they don't seem to work correctly. Anybody got any they could recommend me?

Yakuza

The one I used to use (when I was programming in Java 10 years ago) was Decafe. I've no idea whether it is still around, or if there isn't something better around now. Hope that helped.

NerfNerder

Cheers for that. I'll have a look! Thanks.

NerfNerder

Hi just wondering if anyone knows of any other decompilers. I tried the one suggested however it doesn't produce completely accurate results as it produced a load of goto statements in the code which aren't statements in java. Many thanks for any responses.

Yakuza

The author of class you're looking at has probably used an obfuscator, which is designed to hide the inner workings of the class from decompilers, so no matter what one you use, you might never get a 100% accurate code listing.

CuLT

Ah, the ol' reverse-engineering-the-college-project-example technique - a classic

Naikon

Reverse engineering is a very time consuming process. It's wiser to search for similar code that may or may not conform to the specs you want. Modify it and include citation and you are good to go.

CreepingDeath

JAD used to be okay for JDK 1.4.2.
Might be a little out of date now if your target class used 1.5+ specific features.
Assumes that there's no obfuscation either.

typesafe

There is also a way to decompile Java files online without installing anything using Online Java Decompiler

SaltyJohn

NerfNerder wrote: »

Anybody know a good java decompiler that actually works? I've tried a few I found on google but they don't seem to work correctly. Anybody got any they could recommend me?

Without a doubt the best one I've seen is the one Intellij uses (Fernflower I believe it is called). You end up pretty much with the source code except for a few little differences in enhanced for loops compiling to indexed loops and little compiler optimisations...nothing that really affects the readability of the code. Variables names are gone, but the compiler does a good job of naming them anyway. Only very complex business logic with lots of mathematical or bitwise operations tends to be confusing for me, due to the loss of variable names.

mad turnip

http://java-decompiler.github.io/

I've had decent results with this over the past few years.

dotsman

Cavaj ("javac" backwards) was pretty good back in the day. It's been so long since I've had to de-compile anything, not sure if there is better out there.