XZ for Java 1.5 is available at <http://tukaani.org/xz/java.html> and in the Maven Central (groupId = org.tukaani, artifactId = xz). Here is an extract from the NEWS file:
* Fix a wrong assertion in BCJ decoders. * Use a field instead of reallocating a temporary one-byte buffer in read() and write() implementations in several classes. -- Lasse Collin | IRC: Larhzu @ IRCnet & Freenode