Failed to implement object rotation towards mouse JAVA

Question

As title say, just can't do it. Attempted for long time and still fail. (I'm new to java)
My Image or fillRect rotate a little bit but not as it should rotate
Whole code +imgs

    *MAIN game class*
    package game.main;

    import java.awt.Canvas;
    import java.awt.Color;
    import java.awt.Graphics;
    import java.awt.image.BufferStrategy;

    public class game extends Canvas implements Runnable{

        private static final long serialVersionUID = -392333887196083915L;

        public static final int WIDTH = 640, HEIGHT = WIDTH / 12 * 9;
        private Thread thread;
        private boolean running = false;

        private Handler handler;

        public game(){

            handler = new Handler();

            new window(WIDTH, HEIGHT,"Game",this);

            handler.addObject(new Player(WIDTH/2-32, HEIGHT/2-32, ID.Player, handler));
        }

        public synchronized void start(){
            thread = new Thread(this);
            thread.start();
            running = true;
        }
        public synchronized void stop(){
            try{
                thread.join();
                running = false;
            }catch(Exception e){
                e.printStackTrace();
            }
        }
        // ↓ game loop for update
        public void run(){
            this.requestFocus();
            long lastTime = System.nanoTime();
            double amountOfTicks = 60.0;
            double ns = 1000000000 / amountOfTicks;
            double delta = 0;
            long timer = System.currentTimeMillis();
            int frames = 0;
            while(running){
                long now = System.nanoTime();
                delta += (now - lastTime) / ns;
                lastTime = now;
                while(delta >= 1){
                    tick();
                    delta--;
                }
                if(running)
                    render();
                frames++;

                if(System.currentTimeMillis() - timer > 1000){
                    timer += 1000;
                    System.out.print("FPS:" + frames);
                    frames = 0;
                }
            }
            stop();
        }

        private void tick(){
                    handler.tick();             
                }

        private void render(){
            BufferStrategy bs = this.getBufferStrategy();
            if(bs == null){
                this.createBufferStrategy(3);
                return;
            }

            Graphics g = bs.getDrawGraphics();

            g.setColor(Color.black);
            g.fillRect(0, 0, WIDTH, HEIGHT);

            handler.render(g);

            g.dispose();
            bs.show();
        }



        public static void main(String args[]) {
            new game();
        }


    }
<br>
package game.main;

import java.awt.Graphics;

public abstract class GameObject {

    protected float x, y;
    protected ID id;
    protected float velX, velY;

    public GameObject(float x, float y, ID id){
            this.x = x;
            this.y = y;
            this.id = id;
    }

    public abstract void tick();
    public abstract void render(Graphics g);

    public void setX(int x){
        this.x = x;
    }
    public void setY(int y){
        this.y = y;
    }   
    public float getX(){
        return x;
    }
    public float getY(){
        return y;
    }
    public void setId(ID id){
        this.id = id;
    }
    public ID getId(){
        return id;
    }
    public void setVelX(int velX){
        this.velX = velX;
    }
    public void setVelY(int velY){
        this.velY = velY;
    }
    public float getVelX(){
        return velX;
    }
    public float getVelY(){
        return velY;
    }
}

*GameObject class*
package game.main;

import java.awt.Graphics;

public abstract class GameObject {

    protected float x, y;
    protected ID id;
    protected float velX, velY;

    public GameObject(float x, float y, ID id){
            this.x = x;
            this.y = y;
            this.id = id;
    }

    public abstract void tick();
    public abstract void render(Graphics g);

    public void setX(int x){
        this.x = x;
    }
    public void setY(int y){
        this.y = y;
    }   
    public float getX(){
        return x;
    }
    public float getY(){
        return y;
    }
    public void setId(ID id){
        this.id = id;
    }
    public ID getId(){
        return id;
    }
    public void setVelX(int velX){
        this.velX = velX;
    }
    public void setVelY(int velY){
        this.velY = velY;
    }
    public float getVelX(){
        return velX;
    }
    public float getVelY(){
        return velY;
    }
}

*Handler class*
package game.main;

import java.awt.Graphics;
import java.util.LinkedList;

// render all objects
public class Handler {

    LinkedList<GameObject> object = new LinkedList<GameObject>();

    public void tick(){
        for(int i = 0; i < object.size(); i++){
            GameObject tempObject = object.get(i);

            tempObject.tick();      
        }
    }
    public void render(Graphics g){
        for(int i = 0; i <object.size();i++){
            GameObject tempObject = object.get(i);

            tempObject.render(g);
        }
    }// handling adding objects
    public void addObject(GameObject object){
        this.object.add(object);
    }   
}

*window class*
package game.main;

import java.awt.Canvas;
import java.awt.Dimension;

import javax.swing.JFrame;

public class window extends Canvas{

    private static final long serialVersionUID = 3010486623466540351L;

    public window(int width, int height, String title, game game){
        JFrame frame = new JFrame(title);

        frame.setPreferredSize(new Dimension(width, height));
        frame.setMaximumSize(new Dimension(width, height));
        frame.setMinimumSize(new Dimension(width, height));

        // X button
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        // ¤ button maximize
        frame.setResizable(false);
        // window appear in middle of screen instead of top left corner
        frame.setLocationRelativeTo(null);
        // add game to window
        frame.add(game);
        frame.setVisible(true);
        game.start();
    }       
}

* ID class*
package game.main;

public enum ID {

    Player();
}

ADDED code only to this class

*Player class*
package game.main;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.MouseInfo;
import java.awt.Point;
import java.awt.PointerInfo;

public class Player extends GameObject{

    Handler handler;

    public Player(int x, int y, ID id, Handler handler) {
        super(x, y, id);
        this.handler = handler;
    }

    public void tick() {
    }
    public void render(Graphics g) {
        ///////////ADDED//////////////////
        PointerInfo a = MouseInfo.getPointerInfo();
        Point b = a.getLocation();
        int mouseX = (int) b.getX();
        int mouseY = (int) b.getY();
        int centerX = game.WIDTH / 2;
        int centerY = game.HEIGHT / 2;
        double angle = Math.atan2(centerY - mouseY, centerX - mouseX) - Math.PI / 2;
        ((Graphics2D)g).rotate(angle, centerX, centerY);
        //////////////////////////////
        g.setColor(Color.white);
        g.fillRect((int)x, (int)y, 32, 32);

    }
}

How it now works and how I want it. WHITE COLOR - original/ GREEN - I want it like that
Example 1
Example 2
I looked in this sources:
Get mouse possition (stackoverflow)
Java 2d rotation in direction mouse point (stackoverflow)
Rotating an object to point towards the mouse

Answer 1

The problem is that MouseInfo.getPointerInfo().getLocation(); returns the absolute mouse location. You need the mouse location relative to your game canvas. You can modify the render method in your game class as follows:

 Point mouseLocation = MouseInfo.getPointerInfo().getLocation();
 SwingUtilities.convertPointFromScreen(mouseLocation, this);
 handler.render(g, mouseLocation);

This requires you to modify the method signatures of your rendering methods accordingly. This is only one way to pass the mouseLocation from your game canvas to your Player's rendering method. Use the mouseLocation instead of MouseInfo.getPointerInfo().getLocation(); in your Player's render method.

There are a few more things you have to change to place the player in the center of the canvas and make him rotate around his center:

• You should set the size of the game canvas instead of the size of the window(JFrame). Do this by calling setPreferredSize(new Dimension(width, height)); on the game canvas and by calling frame.pack() before frame.setVisible(true). This will ensure that your game canvas has exactly the size specified by WIDTH and HEIGHT.
• You could add two fields refx and refy to your GameObject class which describe the reference point of your GameObject (e.g. its center). You could then construct a new Player by calling new Player(WIDTH/2-16, HEIGHT/2-16, 16, 16, ID.Player, handler) where the player's initial position is at (WIDTH/2-16, HEIGHT/2-16) and its reference point is (16,16) - the center of the player when the player is represented by a 32x32 rectangle.
• In the Player's render method initialize the center you want to rotate around with int centerX = Math.round(x + refx); int centerY = Math.round(y + refy); where (x,y) is the position of the object you want to rotate and (refx, refy) the point you want to rotate around relative to the object's position (e.g. x = WIDTH/2-16, y = HEIGTH/2-16, refx = 16, refy = 16).