Java version incompatibility

Got this error message when I posted a JSON message to a little REST server I'm starting:

java.lang.UnsupportedClassVersionError: org/json/JSONObject : Unsupported major.minor version 52.0

It's because the newest version of the org.json library only works with Java 8 and I'm on Java 7. Why it doesn't detect this at compile time, I don't know.
Fix was to roll back from version 20141113 to 20140107.