how to implement interface in java with example

Example 1: java interface

public interface Exampleinterface {
	
  public void menthod1();
  
  public int method2();

}

class ExampleInterfaceImpl implements ExampleInterface {


  	public void method1()
    {
        //code here
    }
  
    public int method2()
  	{
    	//code here
  	}

}

Example 2: creating the functional interface in java

package com.concretepage;

@FunctionalInterface
public interface Calculator {
   long calculate(long num1, long num2);
}