The final Keyword in Java
In Java, final keyword is applied in various context. The final keyword is a modifier means the final class can't be extended, a variable can't be modified, and also a method can't be override.
final classes
The class declared as final can't be subclass or extend. The final class declared as follows :
public final class MyFinalClass
final methods
The final method can be declare as follows:
public final String convertCurrency()
The final method can't be override in a subclass.
final fields
The field declared as final behaves like constant. Means once it is declared, it can't be changed. Before compiling,only once it can be set; after that you can't change it's value. Attempt to change in it's value lead to exception or compile time error.
You can declare the final fields as :
public final double radius = 126.45;
public final int PI = 3.145;
The fields which are declared as static, final and public are known as named constants. Given below a example of named constant :
public class Maths{
public static final double x = 2.998E8;
}
final method arguments
You can also declare method's argument as final. The final argument can't be modified by the method directly.