JAR files not bit-identical

Question

everytime i create one jar file with the same contents of the last one the md5 checksum always change. I believe that is about timestamps and creation dates but i want to have the certain reason. Thanks everyone.

Answer 1

It may happens because your build procedure creates some files every time you run it. For example MANIFEST.MF located under META-INF may contain date, build number etc. So if it is important for you check manifest and other build-generated files.