Jakarta Slide on OC4J

Never give up (referring to this post). Finally got Jakarta Slide server running on OC4J. The issue was with XML stack, there seems to be some sort of differences between the default Oracle XDK and the XML stack used with Slide. Anyways, to get Slide running you should define the Xerces and Xalan parsers as the JAXP factories in the OC4J startup.
Here is a sample startup script for my OC4J:
cd $HOME/oc4j/j2ee/home
-jar oc4j.jar

Xalan and Xerces libraries should be placed under JAVA_HOME/jre/lib/ext and remember to give at least read access to the account running the OC4j container.

JDeveloper 10.1.2 and Linux-x86_64 with JDK 1.5 (64-bit)

For those running on 64-bit Linux (e.g. using AMD64 CPUs) it is possible that you have 64-bit JDK 1.5 pre-installed. This is the case at least with Fedora Core 4.0 (64-bit).

If you want to get 10.1.2 JDeveloper running with JDK 1.5 you might get an error message such as:
Error: Hotspot VM not supported
Error: JDeveloper can't recognize the JDK version

Tha last error message is because of the first. To work around this you should edit the $JDEV_HOME/jdev/bin/jdev.conf -file and comment out the line that shows:
SetJavaVM hotspot

After this you should be able to start JDeveloper 10.1.2.

You might get some weird sticky startup screen showing in front of the initial questionnaire windows. After passing these (either try moving the windows or just pressing Enter) you should be fine with JDeveloper.