The manifest that the newCapsule method was picking up wasn't correct.

The manifest that the newCapsule method was picking up wasn't correct one.

Thus the error of '...does not appear to be a valid capsule' would be thrown since it cannot find the 'Main-Class' entry in the manifest.
However the mechanism to find the manifest that's written in the constructor, works perfectly. So just copied this code snippet over to newCapsule.