Install Custom JDK/JRE Java Runtime
Ubuntu and its many children have java installed but its the open source version. Most times things run better especially if your developing if you use the actual java runtime.
Go to http://java.com/en/download/linux_manual.jsp?locale=en and download the latest or whatever version you want of java. For the following example replace the words in caps with the information you have
Extract the java runtime:
Move the runtime to /opt/ to get it out of the way:
Then as root to make the system know java is there and have it set as the default java run the following commands:
When prompted select your newly installed java and run ""java -version"" in a console window to make sure you have it set up properly.