This is just for the adventurous people. I'd just installed Ubuntu 8.10 - Intrepid Ibex in my laptop because a co-worker force me to use it to access Oracle E-Business Suite

Basically it's the same as Atul Kumar wrote in his page (google it using keyword Access Oracle Apps R12 / 11i from Linux Client - Mozilla Firefox). I had tried to use fedora core 5, 6, 7, 8 and 9 using the steps he gave and it worked.
Here are the steps :
Oracle Apps : 12.0.5 or 12.0.6
JRE needed : 1.5.0_13
JRE version varied depends on your Oracle Apps. You can try to connect using firefox first to know JRE needed for your machine. You can download JRE 1.5.0_13 from Sun in http://java.sun.com/products/archive/j2 ... index.html and choose JRE then download the bin file. You may download rpm.bin file but then you need to convert it to .deb file because Ubuntu doesn't use rpm package.
1. Change to root
$ su ( google to find steps on how to enable root in Ubuntu, it's easy)
2. Copy JRE 1.5.0_13 from your download folder to /opt (I use opt for my JRE installation)
# cp {download folder of your JRE 1.5.0_13) /opt
3. Extract JRE 1.5.0_13 in /opt
# ./JRE 1.5.0_13.bin
this process will create jre1.5.0.13 folder in /opt
4. Change to /usr/lib/firefox-addons/plugins to create soft link
# cd /usr/lib/firefox-addons/plugins
5. Create soft link
# ln -s /opt/jre1.5.0_13/plugin/i386/ns7/libjavaplugin_oji.so ./libjavaplugin_oji.so
Done. Try to open Oracle Apps and it should work.
Now what if we want to use sqldeveloper:
sqldeveloper version : 1.5.3 (you can download sqldeveloper from oracle in http://www.oracle.com/technology/softwa ... index.html)
JDK version : 1.5.0_17
Before you can install sqldeveloper, if you download the noarch.rpm file you need to convert it to deb file either using alien or any other way.
I installed sqldeveloper and JDK in /opt using step 1 - 3 as above.
Before using sqldeveloper, edit sqldeveloper.sh file and add:
export AWT_TOOLKIT=MToolkit
so it would be like this :
#!/bin/bash
export AWT_TOOLKIT=MToolkit
cd "`dirname $0`"/sqldeveloper/bin && bash sqldeveloper $*
After that, open a terminal then type sqldeveloper. It will ask your JDK installation path. Type it (mine is in /opt/jdk1.5.0_17) and sqldeveloper will open. Hope that help. Have a good day.