Maven job fails to build when Sonar is turned on.

Here is the log:
[INFO] — maven-compiler-plugin:3.0:compile (default-compile) @ manage —
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 179 source files to /usr01/var/lib/jenkins/jobs/Mercury Manage Trunk (Nightly)/workspace/target/classes
[INFO] -------------------------------------------------------------
[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: 6.484s
[INFO] Finished at: Wed Nov 13 17:54:57 SGT 2013
[INFO] Final Memory: 12M/212M
[INFO] ------------------------------------------------------------------------

Sonar plugin: 2.2.2
Java JDK: 7u25