XStream cannot loadXML from GroovyScriptEngine created classes

GroovyScriptEngine does not expose it's ClassLoader and therefore objects created and serialized using the GSE cannot be read back in.

eg.
...

Class objectClass = new GroovyScriptEngine().getClassByName(path);
Object obj = objectClass.newInstance();

XStream xstream = new XStream();
FileOutputStream out = new FileOutputStream(new File("myobj.xml"));
xstream.toXML(obj, out);
...
// input stream defs removed
obj = xstream.fromXML(xmlIn);

... causes com.thoughtworks.xstream.alias.CannotResolveClassException:, even if you set new GroovyClassLoader() as xstream's classloader it still cannot resolve the class.

Exposing the ClassLoader would enable this. Attached is a GSE that allows this.