Is There a Quick Way to Delete a File from a Jar/War Without Having to Extract the Jar and Recreate It

Is there a quick way to delete a file from a Jar / war without having to extract the jar and recreate it?

zip -d file.jar unwanted_file.txt

jar is just a zip file after all. Definitely much faster than uncompressing/recompressing.

How do I update one file in a jar without repackaging the whole jar?

-C is changing the local directory, and is looking for hi.png there. It's not controlling where you're trying to inject it into the JAR file.

I would try making a new directory called images, moving your local hi.png into that, making images a child directory of your current working directory, then just run this:

jar uf myfile.jar images\hi.png

Deleting files using a .jar

// Deletes all files and subdirectories under dir.
// Returns true if all deletions were successful.
// If a deletion fails, the method stops attempting to delete and returns false.
public static boolean deleteDir(File dir) {
    if (dir.isDirectory()) {
        String[] children = dir.list();
        for (int i = 0; i < children.length; i++) {
            boolean success = deleteDir(new File(dir, children[i]));
            if (!success) {
                return false;
            }
        }
    }

    // The directory is now empty so delete it
    return dir.delete();
}

How do I unsign a jar?

I don't know the answer, but here is what I would do:

1. Unzip the jar file or files in question (jars are just zips)
2. Look in the META-INF directory for something that was not MANIFEST-MF.
3. Delete that stuff.
4. Open the MANIFEST-MF and remove stuff that looked like it was signature related.
5. rejar.

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