Let's follow Ludo's example, and get the full Java stack, including Java DB (Sun's Apache Derby distribution) for our Ubuntu systems. It is easy: System|Administration|UpdateManager!

Beginning with Ubuntu 7.04, you get the full Java stack for Linux gathered in one place. I remember learning about Java first on both Solaris (the Sparc stations sitting in the math department at Berkeley) and on Linux (the PCs in a basement office in the industrial engineering department). The tradition continues into "sudo apt-get"! While I'm writing about Java, I should probably remind you about CommunityOne, the free event during this year's JavaOne.