Comment 3 for bug 497368

Note: I had this error in 10.04 after doing a dist-upgrade.

I found that the package "jde" was not installed. Since searching for (x)emacs nor java showed the package, it isn't trivial to realize what is missing.

It is semi-unfortunate that the previous java-mode functionality was not preserved when the separate package for jde was added, but I'm willing to believe that it would be technically hard or problematic.