Irritating Java Environment
Debian/Ubuntu has what I think is pretty dumb Java environment.
Basically, jar files are not automatically found in /usr/lib/java/ and JNI libraries are not automatically found in /usr/lib/jni, requiring you to create a goofy little shell script for every Java app you write that sets these things if you need them. Any Java app that uses external JAR files or JNI files (.e.g., SWT) is instantly made non-portable by the fact that you have to set weird system-specific path settings instead of just being able to run java -jar myapp.jar.
The justification for this seems to be, “well, users might have multiple JVMs, and /usr/bin/java alternative might not be set to the most complete/featureful one, and since we only support software packaged officially for Debian**, we just recommend that packagers include scripts that set the specific JVM and classpath and so on they need, and never ever use the essentially useless /usr/bin/java command.”
Here’s an idea: make /usr/bin/java a system wrapper around the chosen alternative that automatically sets things up so the required JAR files located in the manifest of apps are found without the Debian-specific paths and so that the library search path is set so the Debian-specific /usr/lib/jni path is used for loading JNI shared objects. Then shit will actually work. For the users who set their java alternative to point to some incomplete or non-functional JVM, tell them to kiss your ass and install a JVM that will actually work.
** And this, folks, is still the #1 usability killer in Linux. If it isn’t part of the pre-selected set of almost certainly out of date software packages shipped by the specific version of the specific distribution you’re running, the software is a complete and total bitch to install and use, even when that software happens to be something designed from the ground-up to be portable between distros (or even OSes) in binary format. Packaging systems, for all their benefits, are to many non-technical users just one gigantic artificial barrier to ease of use. The Microsoft software installation model, for all its flaws, actually freaking works when it comes time to install something released after the OS install CD you have was shipped. Linux is the easiest OS in the world to use, so long as you only use it for the things the distro package set says you can.