Pack200, specified in JSR 200, deprecated in JEP 336 and removed in JEP 367, is a compacting archive format developed by Sun, capable of reducing JAR file sizes by up to a factor of 9, with a factor of 3 to 4 seen in practice. Pack200 is optimized for compressing JAR archive files, specifically the Java bytecode portion of the JAR files. Applications of this technology include faster Java application deployment over Java Web Start.