My game source

Entity.java

package net.rymate.gaming;

import java.util.ArrayList;

import org.newdawn.slick.GameContainer;
import org.newdawn.slick.Graphics;
import org.newdawn.slick.Image;
import org.newdawn.slick.geom.Shape;
import org.newdawn.slick.geom.Vector2f;
import org.newdawn.slick.state.StateBasedGame;

public abstract class Entity {

	int id;
	Vector2f position;
	float scale;
	float rotation;
	String name;
	Image img;
	float x;
	float y;
	
	public Entity(int id) {
		this.id = id;
		this.img = null;
		position = new Vector2f(0, 0);
		scale = 1;
		this.name = "Anon";
		rotation = 0;
	}

	public Vector2f getPosition() {
		return position;
	}

	public float getScale() {
		return scale;
	}

	public float getRotation() {
		return rotation;
	}
	
	public String getName() {
		return name;
	}
	
	public void setName(String n) {
		this.name = n;
	}

	public int getId() {
		return id;
	}

	public void setPosition(float x, float y) {
		position.set(x, y);
	}

	public void setRotation(float rotate) {
		rotation = rotate;
	}

	public void setScale(float scale) {
		this.scale = scale;
	}

	public abstract void update(GameContainer gc, StateBasedGame sb, int delta);

	public abstract void render(GameContainer gc, StateBasedGame sb, Graphics gr);
}

EntityPlane.java

package net.rymate.gaming;

import org.newdawn.slick.GameContainer;
import org.newdawn.slick.Graphics;
import org.newdawn.slick.Image;
import org.newdawn.slick.Input;
import org.newdawn.slick.SlickException;
import org.newdawn.slick.geom.Vector2f;
import org.newdawn.slick.state.StateBasedGame;

public class EntityPlane extends Entity{

	public EntityPlane(int id) throws SlickException {
		super(id);
		this.img = new Image("data/plane.png");
		//setPosition(new Vector2f(400, 300));
	}

	@Override
	public void update(GameContainer gc, StateBasedGame sb, int delta) {
	      Input input = gc.getInput();

	      if (input.isKeyDown(Input.KEY_A)) {
	         img.rotate(-0.2f * delta);
	      }

	      if (input.isKeyDown(Input.KEY_D)) {
	         img.rotate(0.2f * delta);
	      }

	      if (input.isKeyDown(Input.KEY_W)) {
	         float hip = 0.4f * delta;

	         float rotation = img.getRotation();

	         x += hip * Math.sin(Math.toRadians(rotation));
	         y -= hip * Math.cos(Math.toRadians(rotation));
	      }
	     
		setPosition(x, y);
	}

	@Override
	public void render(GameContainer gc, StateBasedGame sb, Graphics gr) {
		img.draw(position.x, position.y);		
	}

}

Main.java

package net.rymate.gaming;

import java.io.File;
import org.lwjgl.LWJGLUtil;
import org.newdawn.slick.*;
import org.newdawn.slick.geom.Vector2f;

public class Main extends BasicGame {

	public static String title = "Rymate Test Shooter";
	Entity land;
	EntityPlane plane;
	Entity bullet;
	float maxX = 800;
	float maxY = 600;

	public Main(String title) {
		super(title);
	}

	@Override
	public void init(GameContainer gc) throws SlickException {
		plane = new EntityPlane(1);
		plane.setPosition(400, 300);
	}
	    
	@Override
	public void update(GameContainer gc, int delta) throws SlickException {
		//land.update(gc, null, delta);
		plane.update(gc, null, delta);
		//bullet.update(gc, null, delta);
	}
	

	public void render(GameContainer gc, Graphics g) throws SlickException {
		//land.render(gc, null, g);
		plane.render(gc, null, g);
		//bullet.render(gc, null, g);
	}

	public static void main(String[] args) throws SlickException {
		System.setProperty("org.lwjgl.librarypath",
				new File(new File(System.getProperty("user.dir"), "native"),
						LWJGLUtil.getPlatformName()).getAbsolutePath());
		System.setProperty("net.java.games.input.librarypath",
				System.getProperty("org.lwjgl.librarypath"));
		AppGameContainer app = new AppGameContainer(new Main(title));
		app.setDisplayMode(800, 600, false);
		app.setSmoothDeltas(true);
		app.setShowFPS(true);
		app.start();
	}
}