extending Interface - multiple inheritance

 In Java, interfaces can be extended using the extends keyword. This allows you to build a more complex interface by inheriting from one or more existing interfaces.

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✅ Syntax for Extending Interfaces

interface A {
    void methodA();
}

interface B extends A {
    void methodB();
}

Here, interface B extends interface A. So any class that implements B must implement both methodA() and methodB().

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✅ Example

interface A {
    void methodA();
}

interface B extends A {
    void methodB();
}

class MyClass implements B {
    public void methodA() {
        System.out.println("methodA from interface A");
    }

    public void methodB() {
        System.out.println("methodB from interface B");
    }
}

public class Main {
    public static void main(String[] args) {
        MyClass obj = new MyClass();
        obj.methodA();
        obj.methodB();
    }
}

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✅ Extending Multiple Interfaces

Java supports multiple interface inheritance, so one interface can extend multiple interfaces.

interface X {
    void methodX();
}

interface Y {
    void methodY();
}

interface Z extends X, Y {
    void methodZ();
}

Any class that implements Z must provide implementations for methodX(), methodY(), and methodZ().

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🚫 Note

• You can only extend interfaces from other interfaces.

• A class cannot extend an interface, it must implement it.