Instantiate object from class name as string

Let's say have a class name as string.

String myClass = "com.whatever.MyClass";

How can I instantiate this class using reflection and have an object of type MyClass and not Object, without using code like this:

MyClass myObj = MyClass.class.cast(instance);

Basically I want to convert an instance of Object to MyClass without using MyClass in code and just by knowing the class name as string.