Especially if you want to transfer objects from and to a Android mobile device, XML serialization may be an option. XStream is a popular XML serialization tool, however it does not work out-of-the-box with Google Android. Although serialization works, the current XStream 1.2.2 has problems deserializing it: it throws an com.thoughtworks.xstream.converters.ConversionException caused by a java.lang.NullPointerException. Fortunately, this was easy to fix and in the course of patching XStream I stripped XStream down a bit. By removing classes that do not work on Android anyway, I could reduce it by about 20%.

Donwload patched XStream 1.2.2 for Android (Java Source)