That's because Java Control Panel shows version of JRE for normal Mac user, but command line on Terminal shows version of JDK. To update JDK version, need to download the full package from Oracle website.
Older JDK version won't be replace automatically to allow us to switch back if we want. So we have to manually remove it by following the instruction here http://docs.oracle.com/javase/8/docs/technotes/guides/install/mac_jdk.html#A1096903
Credit: http://stackoverflow.com/a/28254333
