ubuntu 设置 默认的JDK路径

　　首先查询有多少种JDK已经被安装了

　　sudo update-alternatives --list java

　　其次 配置你想默认的JDK

　　sudo update-alternatives --config java

There are 2 choices for the alternative java (providing /usr/bin/java).

Selection Path Priority Status

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* 0 /usr/lib/jvm/java-6-openjdk/jre/bin/java 1061 auto mode

1 /usr/lib/jvm/java-6-openjdk/jre/bin/java 1061 manual mode

2 /usr/lib/jvm/java-6-sun/jre/bin/java 63 manual mode

Press enter to keep the current choice[*], or type selection number: 2

此外有些需要编译的 还需要设定 javac 和 javadoc

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