Is there a quick way to delete a file from a Jar / war without having to extract the jar and recreate it?

Question

zip -d file.jar unwanted_file.txt

jar is just a zip file after all. Definitely much faster than uncompressing/recompressing.

In Java you can copy all the entries of a jar except the one you want to delete. i.e. you have to make a copy but don't need to create the individual files.

You can do this by

• creating a new jar.
• iterating though the Jar you have
• copy the entry from one jar to the other, skipping any files you want.
• close and replace the orginal jar if you want.