What's New (original) (raw)

The Java class file format has been updated because of JSR 292, Java Virtual Machine Support for Non-Java Languages. Consequently, the Pack200 engine has been updated accordingly to ensure that Java SE 8 class files are compressed effectively. In particular, the Pack200 engine now recognizes constant pool entries and new bytecodes introduced by JSR 292.

As a result, compressed files created with this version of pack200 will not be compatible with older versions of unpack200.

In general, if a compressed file contains Java SE 8 or Java SE 7 class files, then it will not be compatible with older unpackers. (For example, if a compressed file contains Java SE 7 class files, then it will not be compatible with unpackers from Java SE 6 or earlier.)

See Section 30.2, "Deploying JAR Files Compressed with Pack200" and RFE 6981776.