Allowing only defined classes to access the method in Java

If you wonder how do you allow only a specific class to be allowed to access your method. Here you go. You can check the class name on the stack and do take a decision whether you allow are reject permission to.

Class callerClass = Reflection.getCallerClass(2); //2 stack position
If(!validList_.contains(callerClass)) {
Throw new IllegalAccessException(); or SecurityException();
}

In the above snippet validList is list of classes you wish to allow. This is barrowed from the sun.misc.Unsafe classe.