What I've found extremely useful for parsing JSON is Google's gson library. For xml, you can use gson underneath to do the same thing with gson-xml. With a single line of code you can map your JSON/XML to your objects without having to write a single line of parsing code.
If you find performance to be an issue (I'm making this suggestion because these libs make you super productive), there are mechanisms in both to allow you finer grained control. I doubt you'll have problems with performance though.