LINUX - ubuntu 12.04 Install JDK

Install JDK
1. download jdk-7u3-linux-i586.tar.gz from http://www.oracle.com/...ads-1591156.html
2. tar -xvf ~/Downloads/jdk-7u3-linux-i586.tar.gz
3. sudo mkdir -p /usr/lib/jvm/jdk1.7.0
4. sudo mv jdk1.7.0_03/* /usr/lib/jvm/jdk1.7.0/
5-1. sudo update-alternatives --install "/usr/bin/java" "java" "/usr/lib/jvm/jdk1.7.0/bin/java" 1
5-2. sudo update-alternatives --install "/usr/bin/javac" "javac" "/usr/lib/jvm/jdk1.7.0/bin/javac" 1
5-3. sudo update-alternatives --install "/usr/bin/javaws" "javaws" "/usr/lib/jvm/jdk1.7.0/bin/javaws" 1

Combine Firefox & jre
1. mkdir ~/.mozilla/plugins/
2. ln -s /usr/lib/jvm/jdk1.7.0/jre/lib/i386/libnpjp2.so ~/.mozilla/plugins/
3. go to test page : http://www.java.com/en/download/testjava.jsp & see result as below

cf : http://hi.baidu.com/mucenl/blog/item/3415d5a7c688cab4d0435869.html