Switching easily between Java JDKs on Mac OS X

A quick tip for switching between multiple Java JDK versions on Mac OS X using shell aliases. By adding aliases like `setJdk6`, `setJdk7`, and `setJdk8` to `~/.profile`, each pointing to the `/usr/libexec/java_home` utility with the appropriate version flag, developers can easily change the active JDK from the command line without manual configuration.