ubuntu 12.04 64 bit install java

To install java requires 5 steps

1. Download java
   http://java.com/en/download/index.jsp
   choose the linux x64
2. unpack
   tar -xvf <downloaded file>
3. move to desired directory(assume /usr/local/java)
4. maybe chown -R root:root /usr/local/java
5. add /usr/local/java/bin to path and set environment variable CLASSPATH to /usr/local/java/lib by adding to .profile:
   # add java bin to path
PATH="/usr/local/java/bin:$PATH"
# set java classpath
CLASSPATH="/usr/local/java/lib"


test by running
java -version