How run jar files from a Jlist

Question

I can already run my jar from command prompt
With java -jar me.jar.
But having a few problems with a list. Here's a bit of code I've atempted to try.
String filename = (directory + "/" +(String)mylist.getSelectedValue());
                    String name = filename.substring(51,filename.indexOf("."));
                    //String name = filename.substring(51);
                   Runtime rt = Runtime.getRuntime();
                   try
                         Process p = rt.exec("java -jar" + name);
                    catch(IOException e){}
                    System.out.println(name);

Answer 1

There may be much more wrong but since you use
java -jar me.jar
then I would expect the name in
Process p = rt.exec("java -jar" + name);
to include the ".jar" not exclude it has you have done.
Also, why not not
Process p = rt.exec("java -jar " + filename); // Note the space I added after the -jar
since you seem to have the full path in the string referenced by filename.
P.S. I just love the magic number 51 !