Update a file inside a JAR in a specific directory with jar command

Question

So I\'ve been looking high and low for an answer to this and obviously haven\'t found a satisfactory answer.

The problem is that I want to update a JAR (or any file

Answer 1

I think this is due to how the classes in the java.util.zip package work. They sit on top of streams.

The ZipFile class is built on top of a ZipFileInputStream. Writing zipfiles is done by feeding the ZipEntries one by one to a ZipOutputStream.

I assume the jar executable is built on top of these classes.