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

If you want to sort objects but if class didn't implement Comparable or Comparator, then you will get ClassCastException For example

class Animal{
   int age;
   String type;

   public Animal(int age, String type){
      this.age = age;
      this.type = type;
   }
}
public class MainCls{
   public static void main(String[] args){
       Animal[] arr = {new Animal(2, "Her"), new Animal(3,"Car")};
       Arrays.sort(arr);
   }
}

Above main method will throw below runtime class cast exception

Exception in thread "main" java.lang.ClassCastException: com.default.Animal cannot be cast to java.lang.Comparable