How can I add files to a Jar file?

Question

I want to add a series of files previously extracted from other files(already done) to a jar. These files will be overwriting files inside the JAR. What is the most efficien

Answer 1

Just to add to the existing answers, there is at least one special case: so-called executable JAR files. If you add another JAR file as a dependency -- whether you use jar or zip -- it will complain that the embedded file is compressed:

Caused by: java.lang.IllegalStateException: Unable to open nested entry 'BOOT-INF/lib/file.jar'. It has been compressed and nested jar files must be stored without compression. Please check the mechanism used to create your executable jar file

The solution to this is to use the 0 option to jar:

jar uvf0 myfile.jar BOOT-INF/lib/file.jar

You don't need this for normal class files.