JAVA EE: Java Tutorial : Java Nested Interface(Inside Interface)

Friday, 15 January 2016

Java Tutorial : Java Nested Interface(Inside Interface)

Click here to watch in Youtube :
https://www.youtube.com/watch?v=vkht5Vl1ahg&index=33&list=UUhwKlOVR041tngjerWxVccw

Click the below Image to Enlarge

Java Tutorial : Java Nested Interface(Inside Interface)

OuterInterface.java

public interface OuterInterface
{
    void outerMethod();     
    
    public interface NestedInterface
    {
        void nestedMethod();
    }
}

MyClass.java

/*
 * As you can see in the below example, we are accessing the 
 * NestedInterface by its OuterInterface because 
 * it cannot be accessed directly. 
 * 
 * It is just like apple inside the box, we cannot access the apple directly 
 * because we must open the box first. 
 * 
 * In collection framework has provided a nested interface 
 * Entry. Entry is the sub-interface of Map i.e. accessed by Map.Entry.
 */

public class MyClass implements OuterInterface.NestedInterface
{

    @Override
    public void nestedMethod()
    {
        System.out.println("Nested Method has been called.");

    }

}

InterfaceTest.java

public class InterfaceTest
{

    public static void main(String[] args)
    {
        OuterInterface.NestedInterface nestedInterfaceRef = new MyClass();
        nestedInterfaceRef.nestedMethod();
    }

}

Output