XZ for Java 1.7 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 LZMA2InputStream.available() which could return a too high value in case of uncompressed LZMA2 chunks. This incorrect value was visible via other available() methods too, for example, XZInputStream.available(). * Add the ArrayCache API. It's a pool-like API to reuse large byte and int arrays between compressor and decompressor instances. If you are (de)compressing many tiny files in a row, taking advantage of this API can improve performance significantly. -- Lasse Collin | IRC: Larhzu @ IRCnet & Freenode