Sun JDS

The Sun Java Desktop System is a comprehensive, secure enterprise desktop solution that consists of a fully integrated client environment based on open source components and industry standards, including a Gnome desktop environment, StarOffIce Office Productivity Suite, Mozilla browser, Evolution mail and calendar, Java 2 Platform, Standard Edition (J2SE platform) and a Linux operating system.

In other words, it's a GNU/Linux distro from Sun.

Java here is used as a brand name and, although JDS comes with good Java support, it is mostly not built on Java technology.

Starting from version 3, JDS is Solaris and OpenSolaris default graphic environment and no more use GNU/Linux as it's underlying O/S.