Re-compile a Java Class from Jar

Question

I have an executable jar that has one class file with a wrong value. I requested that file from the author and corrected the value.

Now I want to compile it and add

Answer 1

Once you've compiled the new file (such as in Mr. Will's answer), you can add the new file to the jar using:

jar uf C:\folder\where\jar\is\the_jar_file.jar file.class