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Deriving a Class in Java
A class can be derived from the base class in Java by using the extends keyword. This keyword is basically used to indicate that a new class is derived from the base class using inheritance. It can also be said that it is used to extend the functionality of the class.
A program that demonstrates this is given as follows:
Example
class A { void funcA() { System.out.println("This is class A"); } } class B extends A { void funcB() { System.out.println("This is class B"); } } public class Demo { public static void main(String args[]) { B obj = new B(); obj.funcA(); obj.funcB(); } }
Output
This is class A This is class B
Now let us understand the above program.
The class A contains a member function funcA(). The class B uses the extends keyword to derive from class A. It also contains a member function funcB(). A code snippet which demonstrates this is as follows:
class A { void funcA() { System.out.println("This is class A"); } } class B extends A { void funcB() { System.out.println("This is class B"); } }
In the main() method in class Demo, an object obj of class B is created. Then the functions funcA() and funcB() are called. A code snippet which demonstrates this is as follows:
public class Demo { public static void main(String args[]) { B obj = new B(); obj.funcA(); obj.funcB(); } }