Help with shooting

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

public class Arrow extends Actor
{
    public void act()
    {
        setLocation(getX() + speed, getY());
        checkBoundaries();
        destroyEnemies();
    }
    
    public void checkBoundaries()
    {
        if(getX() > getWorld().getWidth() - 1) 
            getWorld().removeObject(this);
        else if(getX() < 1) 
            getWorld().removeObject(this);
        if(getY() > getWorld().getHeight() - 1) 
            getWorld().removeObject(this);
        else if(getY() < 1) 
            getWorld().removeObject(this);
    }
    
    public void destroyEnemies()
    {
        Actor Zombie = getOneIntersectingObject(Zombie.class);
        if(Zombie != null) {
            getWorld().removeObject(Zombie);
            getWorld().removeObject(this);
        }
    }
    private int speed = 10;
}