The below code generates no compilation error in eclipse but throws error during Runtime.<\/p>\n
\r\npublic class Animal\r\n{\r\n public void eat(){}\r\n}\r\npublic class Dog extends Animal\r\n{\r\n public void eat(){}\r\n public void main(String[] args)\r\n {\r\n Animal animal=new Animal();\r\n Dog dog=(Dog) animal;\r\n }\r\n}\r\n<\/pre>\nOutput<\/strong><\/p>\n\r\nException in thread \"main\" java.lang.ClassCastException: com.mugil.wild.Animal cannot be cast to com.mugil.wild.Dog\r\n\tat com.mugil.wild.Dog.main(Dog.java:12)\r\n\r\n<\/pre>\nBy using a cast you’re essentially telling the compiler “trust me. I’m a professional, I know what I’m doing and I know that although you can’t guarantee it, I’m telling you that this animal variable is definitely going to be a dog<\/p>\n
Because you’re essentially just stopping the compiler from complaining, every time you cast it’s important to check that you won’t cause a ClassCastException by using instanceof in an if statement.<\/p>\n
Generally, downcasting is not a good idea. You should avoid it. If you use it, you better include a check: <\/p>\n
Animal animal = new Dog();<\/p>\n
if (animal instanceof Dog)
\n{
\n Dog dog = (Dog) animal;
\n}<\/p>\n","protected":false},"excerpt":{"rendered":"
The below code generates no compilation error in eclipse but throws error during Runtime. public class Animal { public void eat(){} } public class Dog extends Animal { public void eat(){} public void main(String[] args) { Animal animal=new Animal(); Dog dog=(Dog) animal; } } Output Exception in thread “main” java.lang.ClassCastException: com.mugil.wild.Animal cannot be cast to… Continue reading