Answer:
A jar file is essentially just a structured ZIP file. You can view the contents easily by temporarily changing the extension from .jar to .zip, and then using any compression utility to extract and view the contents. Don't forget to change the extension back to .jar when you are done!

A side note, it is not recommended to make changes to jar files in this manner - the compression utilities do not correctly compress the files in every case, and they do not always include the manifest file required for it to work. If you want to change the contents, you are better off rebuilding the jar file from within an IDE.

First answer by Jvanderb. Last edit by Jvanderb. Contributor trust: 96 [recommend contributor recommended]. Question popularity: 1 [recommend question].