Can't change default jre even though path has been modified

Problem:

The Path in environment variable is using JDK1.6 but java -version shows actually JRE 1.7 is being used.

Solution:

I am on a Windows 7 machine. I am using this way but I don't like it.

Go to C:\Windows\System32, change the java.exe and javaw.exe to whatever you like.
Then the system will pick up the setting in Path.