which javac
返回/usr/bin/javac
file /usr/bin/javac
返回/usr/bin/javac: symbolic link to `/etc/alternatives/javac‘
然后file /etc/alternatives/javac
返回/etc/alternatives/javac: symbolic link to `/usr/lib/jvm/java-6-sun/bin/javac‘
然后file /usr/lib/jvm/java-6-sun/bin/javac
返回/usr/lib/jvm/java-6-sun/bin/javac: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.2.5, not stripped
到此为止，说明路径是/usr/lib/jvm/java-6-sun/bin/，在Eclipse里面设置即可。
ubuntu下查找jdk安装位置
原文：http://www.cnblogs.com/zhaopengcheng/p/6517995.html
