AdoptOpenJDK
Support for an External Pack200 Component
Since the JDK's native pack200 implementation has been removed from newer JDKs, it would be great if this implementation could be supported. See also: https://github.com/martinhickson/IcedTea-Web-1/wiki for code examples.
Hey, just coming to support this request as the service processors on older servers may use Pack200 for their JAR files and they won't work on newer JDKs. Here's a write up of someone's findings and that they've had to fall back to an ancient JDK version: https://forums.debian.net/viewtopic.php?t=158747
It does look like the original poster managed to get past this. @hendrikebbers may be able to help in the future though.
Yup, by updating a fork of the Pack200 code from JDK11 to compile with JDK17 and updating IcedTea to use it. This'd be great have back in the official release.
I started to add in support for the Pack200 class that is in Apache Commons Compress (which appears to have been Martin's initial approach as well) and it is a game of whack-a-mole to fix/add things which I haven't finished.
See also: https://github.com/martinhickson/pack200/wiki, which relates to a fork of the pack200 project, where changes to attribute handling in the ClassWriter class (see the commit history), achieved full pack200 binary compatibility with the JDK 11 packer. The reason I stopped using the Apache Commons Compress Pack200 class was that it appeared to be targeting an earlier version of the JDK.