I need to decide on which one to use. My case is pretty simple. I need to convert a simple POJO/Bean to XML, and then back. Nothing special.
One thing I am looking for
I would also suggest Simple, take a look at the tutorial, there and decide for yourself. The mailing list is very responsive and you will always get a prompt answer to any queries.
I'd recommend that you take a look at Simple
Simple is much slower then XStream(in serialization objects to xml)
http://pronicles.blogspot.com/2011/03/xstream-vs-simple.html
Just from reading the documentation (I'm facing down the same problem you are, but haven't tried either way yet; take this with a grain of salt):
XSTREAM
SIMPLE
Handles versioning by being non-strict in parsing whenever the class is right, but the version is different. (i.e., if you added two fields and removed one since the last version, it'll ignore the removed field and not throw an exception, but won't set the added fields.) Like XStream, it doesn't seem to have a way to migrate data from one version to the next, but unlike XStream, there's no external library to step in and handle it. Presumably, the way to handle this is with some external function (and maybe a "version" variable in your class?), so you do
Stuff myRestoredStuff = serializer.read(Stuff.class, file); myRestoredStuff.sanityCheck();
Commonly-used (de)serializing adjustments are made by adding/editing annotations, but there's support for writing your own (de)serialization functions to override the standard methods if you need to do something woolly.
Why not use JAXB instead?
Useful resources:
Was taking a quick look at simple while reading stackoverflow; as an amendment to Paul Marshalls helpful post, I thought i'd mention that Simple does seem to support versioning through annotations-
http://simple.sourceforge.net/download/stream/doc/tutorial/tutorial.php#version