What makes an object assignment-compatible with another class?

Question

I\'m wondering what specifically allows an object of one class to be cast as another class. Looking at the Class.isInstance(Object obj) javadoc, it suggests that an object

Answer 1

Thrown to indicate that the code has attempted to cast an object to a subclass of which it is not an instance. For example, the following code generates a ClassCastException:

 Object x = new Integer(0);
 System.out.println((String)x);

more info here and here.