Explanation of “ClassCastException” in Java

Question

I read some articles written on \"ClassCastException\", but I couldn\'t get a good idea on that. Is there a good article or what would be a brief explanation?

Answer 1

Do you understand the concept of casting? Casting is the process of type conversion, which is in Java very common because its a statically typed language. Some examples:

Cast the String "1" to an int -> no problem

Cast the String "abc" to an int -> raises a ClassCastException

Or think of a class diagram with Animal.class, Dog.class and Cat.class

Animal a = new Dog();
Dog d = (Dog) a; // No problem, the type animal can be casted to a dog, because its a dog.
Cat c = (Dog) a; // Raises class cast exception; you can't cast a dog to a cat.