Create an interface called Runner. The interface has an abstract method called run() that displays a message describing the meaning of run to the class. Create classes called Machine, Athlete, and PoliticalCandidate that all implement Runner. The run() should print the following in each class:
Machine - When a machine is running, it is operating.
Athlete - An athlete might run in a race, or in a game like soccer.
PoliticalCandidate - A political candidate runs for office.

public class Athlete implements Runner
{
public void run()
{
// write your code here
}
}

public class DemoRunners
{
public static void main(String[] args)
{
Machine runner1 = new Machine();
Athlete runner2 = new Athlete();
PoliticalCandidate runner3 = new PoliticalCandidate();
runner1.run();
runner2.run();
runner3.run();
}
}

public class Machine implements Runner
{
public void run()
{
// write your code here
}
}

public class PoliticalCandidate implements Runner
{
public void run()
{
// write your code here
}
}

public interface Runner
{
// write your code here
}

Here is the interface Runner:

public interface Runner  {  //interface Runner

public abstract void run();  } //abstract method run that displays a message describing the meaning of run to the class

/*Here Runner is the interface which is an abstract class. It is used to group related methods such as here is run method with empty body. An abstract method run() does not have a body. The body is provided by the sub classes Machine, Athlete, and PoliticalCandidate that all implement Runner.  */

Explanation:

Here is the Athlete class:

public class Athlete implements Runner  {  //class that implements Runner interface

public void run()  {  //interface method accessed by Athlete to provide its body according to describe the meaning of run to the class

    System.out.println("An athlete might run in a race, or in a game like soccer.");  } }    //prints this message

Here is the Machine class:

public class Machine implements Runner  {

public void run()  {

System.out.println("When a machine is running, it is operating.");  }}

Here is the PoliticalCandidate class:

public class PoliticalCandidate implements Runner  {

public void run()  {

System.out.println("A political candidate runs for office.");  } }

/*To access the interface Runner method run(), the Runner must be "implemented" by Machine, Athlete, and PoliticalCandidate classes with the implements keyword. The body of the interface method run() is provided by the "implement" class */      

Here is the DemoRunners class:

public class DemoRunners {  //class name

public static void main(String[] args)  {  //start of main method

Machine runner1 = new Machine();  //creates object of Machine class

Athlete runner2 = new Athlete();  //creates object of Athlete class

PoliticalCandidate runner3 = new PoliticalCandidate();  //creates object of PoliticalCandidate class

runner1.run();  //uses object of Machine class to call run method

runner2.run();  //uses object of Athlete class to call run method

runner3.run();  } } //uses object of PoliticalCandidate class to call run method

When runner1.run() is called it invokes the run() method of class Machine which displays the message:

When a machine is running, it is operating.

When runner2.run() is called it invokes the run() method of class Athlete which displays the message:

An athlete might run in a race, or in a game like soccer.  

When runner3.run() is called it invokes the run() method of class PoliticalCandidate which displays the message:

A political candidate runs for office.

The screenshot of the program is attached.