Executable JAR files. For an executable JAR file that contains a stand-alone application, a Main-Class attribute should exist that provides the name of the first piece of code for the Java Runtime ...

Receive This file is not a valid 32-bit application error? ... We always recommend downloading executable files from the primary source or the official homepage if you can.

Instead of fixing the source code, it appears that the company's developers made a series of careful changes directly to the buggy program's executable file.