Health for Emeny

//Enemy
private int health = 2;

public void loseHealth(int amount)
{
    health -= amount;
    if (health < 1)
    {
        getWorld().removeObject(this);
    }
}

//Bullet
public void act()
{
    move(2);
    Enemy e = (Enemy) getOneIntersectingObject(Enemy.class);
    if (e != null)
    {
        e.loseHealth(1);
        getWorld().removeObject(this);
    }
}

import greenfoot.*;  // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)

/**
 * Write a description of class Second here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class Second extends Monster
{
    private int horizontalSpeed = -3;
    private int verticalSpeed = 4;
    /**
     * Act - do whatever the First wants to do. This method is called whenever
     * the 'Act' or 'Run' button gets pressed in the environment.
     */
    public void act() 
   {
       bounceAtEdge();
       move(horizontalSpeed , verticalSpeed );
   }
   
   public void move(int changeX, int changeY)   
   {
       int x = getX();
       int y = getY();
       int newX = x + changeX;
       int newY = y + changeY;
       setLocation(newX, newY);
    }
    
   public String hitTheEdge()
   {
       int x  = getX();
       int y = getY();
       World myWorld = getWorld();
       int rightSide = myWorld.getWidth() -1;
       int bottomSide = myWorld.getHeight() -1;
       if(y == 0)
       {
           return "top";
        }else if (x == 0)
        {
            return "left";
        }else if(x == rightSide) {
            return "right";
        }else if (y == bottomSide)
        {
            return "bottom";
        }else {
            return null;
        }
   }
   
    public void bounceAtEdge()
   {
       String edge = hitTheEdge();
       if(edge == "top" || edge == "bottom")
       {
           verticalSpeed = verticalSpeed * -1;
        }else if (edge == "left" || edge == "right")
        {
            horizontalSpeed = horizontalSpeed * -1;
        }
   }  
   
}

import greenfoot.*;  // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)

/**
 * Write a description of class Second here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class Second extends Monster
{
    private int horizontalSpeed = -3;
    private int verticalSpeed = 4;
    /**
     * Act - do whatever the First wants to do. This method is called whenever
     * the 'Act' or 'Run' button gets pressed in the environment.
     */
    public void act() 
   {
       bounceAtEdge();
       move(horizontalSpeed , verticalSpeed );
   }
   
   public void move(int changeX, int changeY)   
   {
       int x = getX();
       int y = getY();
       int newX = x + changeX;
       int newY = y + changeY;
       setLocation(newX, newY);
    }
    
   public String hitTheEdge()
   {
       int x  = getX();
       int y = getY();
       World myWorld = getWorld();
       int rightSide = myWorld.getWidth() -1;
       int bottomSide = myWorld.getHeight() -1;
       if(y == 0)
       {
           return "top";
        }else if (x == 0)
        {
            return "left";
        }else if(x == rightSide) {
            return "right";
        }else if (y == bottomSide)
        {
            return "bottom";
        }else {
            return null;
        }
   }
   
    public void bounceAtEdge()
   {
       String edge = hitTheEdge();
       if(edge == "top" || edge == "bottom")
       {
           verticalSpeed = verticalSpeed * -1;
        }else if (edge == "left" || edge == "right")
        {
            horizontalSpeed = horizontalSpeed * -1;
        }
   }  
   
}

import greenfoot.*;  // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)

/**
 * Write a description of class Lattack here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class Lattack extends Character
{
    /**
     * Act - do whatever the Lattack wants to do. This method is called whenever
     * the 'Act' or 'Run' button gets pressed in the environment.
     */
    public void act() 
    {
        move(-5);
        eatFirst();
    }
    
    public boolean atWorldEdge()
   {
        if(getX() <= 10 || getX() > getWorld().getWidth() - 10)
        return true;
        if(getY() <= 10 || getY() > getWorld().getHeight() - 2)
        return true;
        else 
        return false;
   }  
   
      public void eatFirst()
   {
      Actor First;
      First = getOneIntersectingObject(First.class);
      Actor Second;
      Second = getOneIntersectingObject(Second.class); 
      Actor Third;
      Third = getOneIntersectingObject(Third.class);
      if(First != null)
      {
           World myWorld = getWorld();
           getWorld().removeObject(First);
           Background background = (Background)myWorld;
           Counter counter = background.getCounter();
           counter.addScores();
           getWorld().removeObject(this);
      }else if(Second != null)
      {
           World myWorld = getWorld();
           getWorld().removeObject(Second);
           Background background = (Background)myWorld;
           Counter counter = background.getCounter();
           counter.addScores();
           getWorld().removeObject(this);
      }else if(Third != null)
      {
           World myWorld = getWorld();
           getWorld().removeObject(Third);
           Background background = (Background)myWorld;
           Counter counter = background.getCounter();
           counter.addScores();
           getWorld().removeObject(this);
      }else if(atWorldEdge())
      {
           getWorld().removeObject(this);
      }
   }    
}