A class implements interface but one interface extends another interface.

Example:

interface Simple
{
	void display();
}
interface Simple1 extends Simple
{
	void show();
}
class Demo implements Simple1
{
	public void display()
	{
		System.out.println("JavaRace");
	}
	public void show()
	{
		System.out.println("Welcome to JavaRace");
	}
}
class TestInterface
{
	public static void main(String args[])
	{
		Demo d = new Demo();
		d.display();
		d.show();
	}
}

Output
JavaRace
Welcome to JavaRace