Unpacking a jar file using pack200

[sublixt]

I am trying to unpack a jar file using pack200 but cannot figure out what i am suppose to have in the input stream.

import java.io.*;
import java.util.jar.*;
public class test {
	public static void main(String args[]) throws IOException{
		String userName = System.getProperty("user.home");
		File outName = new File(userName +"/Desktop/test.jar");
		File inName = new File(userName + "/Desktop/tmp");
		Pack200.Unpacker unpacker = Pack200.newUnpacker();
	    JarOutputStream out = new JarOutputStream(new FileOutputStream(outName));
	    InputStream in = new FileInputStream(inName);
	    unpacker.unpack(in, out);
	    out.close();
	}

}

Exception in thread "main" java.io.FileNotFoundException: /home/***/Desktop/tmp (Is a directory)
	at java.io.FileInputStream.open(Native Method)
	at java.io.FileInputStream.<init>(FileInputStream.java:137)
	at test.main(test.java:10)

I know from previous experiences that (Is a directory) means that the path needs to be something other than a directory but what does the path need to be for the pack200 to work?

[pbrockway2]

The exception is saying that there is a problem with the FileInputStream constructor rather than anything to do with Pack200. The File argument must name a readable file.

Check that /home/***/Desktop/tmp exists (including spelling and case), is a file and is readable. Do this from the command line or within the code using the appropriate File methods.

[sublixt]

i took your suggestion, as well as i could understand, and created a file.txt in the tmp directory re wrote the path and now it is giving me a new error

Exception in thread "main" java.io.IOException: Corrupted pack file: magic/ver = 00000000/0.0 should be CAFED00D/150.7 OR CAFED00D/160.1

	at com.sun.java.util.jar.pack.NativeUnpack.start(Native Method)
	at com.sun.java.util.jar.pack.NativeUnpack.run(NativeUnpack.java:186)
	at com.sun.java.util.jar.pack.NativeUnpack.run(NativeUnpack.java:235)
	at com.sun.java.util.jar.pack.UnpackerImpl.unpack(UnpackerImpl.java:121)
	at test.main(test.java:11)

[Norm]

Looks like the unpack() method thinks the pack file it is working on is corrupted.
Does unpack read "packed" files? Or text files?