I found Java 1.7 SDK in `/Library/Java/JavaVirtualMachines/jdk1.7.0_07.jdk`, and all the binaries in `/Library/Java/JavaVirtualMachines/jdk1.7.0_07.jdk/Contents/Home/bin`. 

![enter image description here][1]

And by clicking the jdk file, I could arrange the order so that Java SE 7 is executed first.

    java -version
    java version "1.7.0_07"
    Java(TM) SE Runtime Environment (build 1.7.0_07-b10)
    Java HotSpot(TM) 64-Bit Server VM (build 23.3-b01, mixed mode)

  [1]: https://i.sstatic.net/amf9V.png