“Invalid signature file” when attempting to run a .jar

Question

My java program is packaged in a jar file and makes use of an external jar library, bouncy castle. My code compiles fine, but running the jar leads to the following error:

Answer 1

A strategy would consist in using ANT to simplify the removal of the signature from each Jar file. It would proceed with the following steps:

1. Copying the MANIFEST.MF in a temporary file
2. Removing the Name and SHA entries from the temporary file
3. Creating a temporary Jar file with the temporary manifest
4. Removing the temporary manifest
5. Swapping the original Jar file with the temporary one

Here is an ANT macrodef doing the work:

`

The definition can then be called this way in an ANT task: