使用update-alternatives切换ubuntu下默认java命令 sky@sky-VGN-CR23-B:~$ cd /usr/java/jdk1.7.0_21/sky@sky-VGN-CR23-B:/usr/java/jdk1.7.0_21$ cd ..sky@sky-VGN-CR23-B:/usr/java$ sudo ln -s ./jdk1.7.0_21 ./jdk1.7sky@sky-VGN-CR23-B:/usr/java$ sudo rm jdk-7u21-linux-i586.tar.gz sky@sky-VGN-CR23-B:/usr/java$ sudo update-alternatives –install /usr/bin/java java /usr/java/jdk1.7/bin/java 1update-alternatives: using /usr/java/jdk1.7/bin/java to provide /usr/bin/java (java) in 自动模式sky@sky-VGN-CR23-B:/usr/java$ sudo update-alternatives –config javaThere is only one alternative in link group java (providing /usr/bin/java): /usr/java/jdk1.7/bin/java无需配置。sky@sky-VGN-CR23-B:/usr/java$ java -versionjava version “1.7.0_21″Java(TM) SE Runtime Environment (build 1.7.0_21-b11)Java HotSpot(TM) Server VM (build 23.21-b01, mixed mode)sky@sky-VGN-CR23-B:/usr/java$ ll /usr/bin/javalrwxrwxrwx 1 root root 22 4月 27 01:23 /usr/bin/java -> /etc/alternatives/java*sky@sky-VGN-CR23-B:/usr/java$ ll /etc/alternatives/javalrwxrwxrwx 1 root root 25 4月 27 01:23 /etc/alternatives/java -> /usr/java/jdk1.7/bin/java*sky@sky-VGN-CR23-B:/usr/java$ ll /usr/java/jdk1.7lrwxrwxrwx 1 root root 13 4月 27 01:14 /usr/java/jdk1.7 -> ./jdk1.7.0_21/
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