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

String cmd = "jar uvf " + "jarName" + " " + "Filename";
System.out.println(cmd);
try {
Process p = Runtime.getRuntime().exec(cmd);
}
catch (Exception ex) {
}