從http://java.sun.com中下載jdk:jdk-6u23-linux-i586.bin,存放到/usr/java目錄
1、給權限:sudo chmod u+x /usr/java/jdk-6u23-linux-i586.bin
2、安裝jdk:sudo /usr/java/jdk-6u23-linux-i586.bin
3、設置環境變量:sudo gedit /etc/environment
#set java environment
JAVA_HOME=/usr/java/jdk1.6.0_23
PATH=$PATH:$JAVA_HOME/bin
CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$CLASSPATH
export JAVA_HOME PATH CLASSPATH
4、使上面設置的環境變量生效:#source /etc/environment
5、設置ubuntu的默認jdk,原因使因爲ubuntu默認有openjdk:
sudo update-alternatives --install /usr/bin/java java /usr/java/jdk1.6.0_23/bin/java 300