下载安装:$sudo apt-get install sun-java6-jdk 设置默认的java程序:$sudo update-alternatives --config java 设置环境变量:$sudo gedit /etc/environment 添加以下两行:CLASSPATH=/usr/lib/jvm/java-6-sun/lib JAVA_HOME=/usr/lib/jvm/java-6-sun 查看java版本号:$java -version