A small tool to unpack old runescape jar files. Builds are provided via the releases page and they include bundled JREs. To run this manually you need to run with java versions up to 13 as pack200 support was removed in java 14.
Download one of the release packages or compile yourself then run:
bin/jag-unpacker <path-to-main_file_cache.dat0>
A runescape-unpacked.jar file will be created in the same location as the dat0 file.