Obtaining Manifest from Jar

[Doug Melzer]

I'd like to obtain a version number from a .jar file's manifest, but I'd like to do so without having to know the file location of the .jar file.
Is it possible, given a class that was loaded from the .jar file, to obtain a handle to that .jar file's manifest?

[Thomas Smets]

I believe you will have to work out the jars to find from which file it comes from !
This means that you will have to find all the JAR's in you classpath & find in them where you class source is located ! From there you could search for the MANIFEST file in the current jar !
This could be handy !
Sun's tutorial on how to read Jar from Java !

[Steve Deadsea]

There may well be a way to do it without knowing the name of the jar file. It works for other files in the jar file (but note I haven't tried it with anything in the META-INF directory)
The basic idea is that everything that is in the jar file is in the classpath, and you get a InputStream to a system resource from the classloader. Here is how it might work.

URL url = ClassLoader.getSystemResource("META-INF/MANIFEST.MF");
if (url != null) {
InputStream in = url.openStream());
}

[Doug Melzer]

I've tried a couple of these ideas, but the problem that I encounter is that if there are multiple .jar files on the classpath that I can't ensure I'm reading the desired manifest file.
Thanks for the suggestions!