- You can prevent it by adding the final keyword to the class definition.
- In other words, what used to be
- You cannot subclass this. If you try to extend this class, the compiler will give you an error.
- You can do this with methods, too. You can prevent methods from being extended by adding a final keyword.
- Now, you can subclass the class that contains these methods, but you cannot override these methods.
- Note, all methods in a final class are automatically final. After all, if you can't subclass (extend) the class, how are you going to override the method?
- Declaring a class final does not affect the fields, however.
- public class Thing {
public final class Thing { .
- public void changeSalary() {
- public final void chagneSalary() {
- In general, final classes and methods are more efficient because they use static binding, not dynamic binding.
- You have better control over your class. Imagine if you are a vendor that sells Java classes. There might be some methods that you want to protect, especially methods that gather volume data!
