What is the difference between Base interface and Nested interface?

What is Base interface, Nested interface?
A Base interface is an interface, which is extended by another interface. Below is an example code snippet

interface Ia
public void met1();
public int met2();

interface Ib extends Ia
public double met3(float p);

Also note that an interface can be derived from more than one interface, as shown in below code snippet

interface Id extends Ib, Ic
public float met4();

Methods inside an interface cannot be declared private or final.
Member variables declared in an interface are static and public, implicitly.
Member variables declared in an interface cannot be declared as private.

A nested interface or inner interface is an interface declared inside another interface or class.

Interface cannot be declared within body of a method, unlike an inner class declared inside method body.

If an interface need to be accessed directly using an interface or class.

Below is an example of the same

interface Ix{
	public int met1();

	//interface Iy cannot be declared as private member, in below statement
	interface Iy{
		public void met2();

class Cx{
	private int i;

	interface Iz{
		public float met3();

public class InnerInterfaceDemo implements Ix.Iy, Cx.Iz{

	public static void main(String args[])
		Ix.Iy obj = new InnerInterfaceDemo();
		Cx.Iz obj1 = new InnerInterfaceDemo();


	public void met2()
		System.out.println("met2() method");

	public float met3()
		System.out.println("met3() method");
		return 1.2f;


In java best example for built in interface Entry, java.util.Map.Entry

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