Today I’ve been working on a problem where properties being loaded into our CRM system from a GIS DTF file are doing some strange updates. It appears that the vendor in their wisdom has decided to populate user defined fields that we already use!

The Loader is written in Java, I have a .jar file and can extract the .class files, but they’re all compiled.

A bit of searching reveals an online decompiler I can use:

I started using it to decompile one .class file at a time and quickly became bored. So tried the whole .jar file. It happily decompiled the file and returned a single zip file containing the decompiled .class files as .javafiles.

Now I can scan the .java files to find out what other SQL calls they are making to fill other fields we might be using.