如题，执行sudo mvn -version的时候，显示
Error: JAVA_HOME is not defined correctly. We cannot execute /usr/lib/jvm/java/bin/java
但是mvn -version的时候，执行是正常的，显示：

 Apache Maven 2.2.1 (rdebian-14)
Java version: 1.6.0_30
Java home: /usr/lib/jvm/java/jdk1.6.0_30/jre
Default locale: zh_CN, platform encoding: UTF-8
OS name: "linux" version: "3.13.0-57-generic" arch: "amd64" Family: "unix"

有人知道怎么办的么？