Why does it say 'invalid method declaration; return type required' in line 17.
import greenfoot.*; // (World, Actor, GreenfootImage, Greenfoot and MouseInfo) /** * Write a description of class Level_quatre here. * * @author (your name) * @version (a version number or a date) */ public class Level_quatre extends World { HealthBar healthbar = new HealthBar(); private int time; /** * Constructor for objects of class Level_quatre. * */ public Play() { // Create a new world with 600x400 cells with a cell size of 1x1 pixels. super(1000, 700, 1); time = 6000; point = 0; prepare(); } private void act() { time--; showTime(); } private void showTime() { showText("Time: " + time/100, 50, 50); } public HealthBar getHealthBar() { return healthbar; } /** * Prepare the world for the start of the program. * That is: create the initial objects and add them to the world. */ private void prepare() { addObject(healthbar, 500, 40); SharkSpawner shark_spawner = new SharkSpawner(); addObject(shark_spawner,745,479); shark_spawner.setLocation(927,629); Fishes fishes = new Fishes(); addObject(fishes,810,159); house house2 = new house(); addObject(house2,68,67); house2.setLocation(26,27); } }