title: Updating jar manifest file - java.io.IOException: invalid manifest format
body: <p>I need to update the manifest in my jar file that I create (export) within Eclipse.  I've tried to follow <a href="http://docs.oracle.com/javase/tutorial/deployment/jar/secman.html" rel="noreferrer">this</a> explanation without success.  I'm not quite sure what to specify on the command line.  The Oracle web site is not too clear. I then found a post on SO that said to extract the manifest.mf file from the jar archive, update it, and add it back to the jar archive.  I've tried that too, and it appears to work, however, at runtime, I get <code>java.io.IOException: invalid manifest format</code>.  What is the correct way to update the <strong>manifest.mf</strong> to add new attributes?  An example would be most helpful.</p>