Maven找不到JDK

Question

使用 Oracle JDK 1.7.0_51 运行 Ubuntu 12.04 amd64。

$ which javac
/usr/bin/javac
$ which java
/usr/bin/java

当我尝试运行mvn install我的项目时，我收到这个漂亮的小错误：

[ERROR] COMPILATION ERROR : 
[INFO] -------------------------------------------------------------
[ERROR] No compiler is provided in this environment. Perhaps you are running on a JRE rather than a JDK?
[INFO] 1 error
[INFO] -------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.579s
[INFO] Finished at: Tue Mar 11 13:48:06 PDT 2014
[INFO] Final Memory: 18M/605M

我相当确定我安装了编译器，但它看不到它。

JAVA_HOME被设定为/usr/lib/jvm/java-7-oracle。我需要为 JDK 设置另一个变量吗？