用命令 whereis java就可以看到了
eg:
-bash-3.1$ whereis java
java: /usr/bin/java /etc/java /usr/lib/java /usr/share/java /opt/jdk1.6.0_01/bin/java

如果仅仅想知道java执行路径在那里的话 用which java就可以了
eg:
-bash-3.1$ which java
/usr/bin/java

奈斯