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How to draw an array of Graphics

OK so i'm working on a school project (little animation) and I am currently trying to make rain. I'm not sure how I would go about drawing individual "drops" using JPanel. My Code so far:
Main Class:
public class RainPanel extends JPanel {
private static final long serialVersionUID = 1L;
public static void main(String[] args) {
new RainPanel();
}
private final int WIDTH = 800, HEIGHT = 800;
Drop drop;
public RainPanel() {
init();
}
public void init() {
JFrame frame = new JFrame("Rain");
JPanel drop = new Drop();
frame.setVisible(true);
frame.setSize(WIDTH, HEIGHT);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.add(drop);
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
drop.paint(g);
}
Drop class:
public class Drop extends JPanel implements ActionListener{
private static final long serialVersionUID = 1L;
int x,y;
int yVel = 2;
Timer t = new Timer(5, this);
Random r = new Random();
ArrayList<Drop> DropArray;
public Drop() {
x = r.nextInt(800);
y = r.nextInt(800);
t.start();
}
public void paint(Graphics g) {
super.paintComponent(g);
DropArray = new ArrayList<>(100);
for (int i = 0; i < DropArray.size(); i++) {
DropArray.add(new Drop());
}
g.setColor(Color.BLUE);
g.fillRect(x, y, 3, 15);
}
public void update() {
y += yVel;
if (y > 800)
y = r.nextInt(800);
}
#Override
public void actionPerformed(ActionEvent e) {
update();
repaint();
}
I understand if you might be cringing hard right now (I'm fairly new to graphics coding and mostly familiar with Java itself). All i'm getting drawn currently is a single rain drop. Any suggestions are appreciated.

Don't call super.paintComponent from within paint, you're breaking the paint chain which could cause no end of issues. Override paintComponent directly instead
You shouldn't be modifying the state of a component or anything the component relies on from within any paint method, paint can be called a number of times in quick succession and this can cause no end of issues
Component based animation is not a simple task and unless you really, really need it, you should try and avoid it. Instead, write a class which is "paintable", which you can call from your paintComponent method
For example..
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.Rectangle2D;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class RainDropsKeepFalling {
public static void main(String[] args) {
new RainDropsKeepFalling();
}
public RainDropsKeepFalling() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new RainPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class RainPane extends JPanel {
private List<Drop> drops = new ArrayList<>(100);
public RainPane() {
for (int index = 0; index < 100; index++) {
drops.add(new Drop(getPreferredSize()));
}
Timer timer = new Timer(5, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
for (Drop drop : drops) {
drop.update(getSize());
repaint();
}
}
});
timer.start();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
for (Drop drop : drops) {
Graphics2D g2d = (Graphics2D) g.create();
drop.paint(g2d);
g2d.dispose();
}
}
}
protected static final Random random = new Random();
public static class Drop {
private double vDelta = random.nextDouble() + 0.5;
private int height = 15;
private int width = 3;
private double x;
private double y = -height;
private Rectangle2D shape;
public Drop(Dimension size) {
x = random.nextInt(size.width - width) + width;
y = random.nextInt(size.height - height) + height;
shape = new Rectangle2D.Double(x, y, width, height);
}
public void paint(Graphics2D g2d) {
g2d.setColor(Color.BLUE);
g2d.fill(shape);
}
public void update(Dimension size) {
y += vDelta;
if (y > size.height) {
y = -height;
x = random.nextInt(size.width - width) + width;
}
shape.setRect(x, y, width, height);
}
}
}

how do I make this java awt/ swing animation work?

I'm pretty new to java coding, but i know the basic structures of how to code. I am not familiar with awt/swing, and don't know what my error is.
Background: I searched up ways to animate with java, found zetcode tutorials.
I copy/pasted their code, and tested the program, to make sure it works. the JFrame opened, but nothing drew. Maybe this is a system compatibility error? if so, how would I fix it?
these are the two separate classes:
package com.zetcode;
import java.awt.EventQueue;
import javax.swing.JFrame;
public class ThreadAnimationExample extends JFrame {
public ThreadAnimationExample() {
initUI();
}
private void initUI() {
add(new Board());
setResizable(false);
pack();
setTitle("Star");
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JFrame ex = new ThreadAnimationExample();
ex.setVisible(true);
}
});
}
}
This is the main class.
Board.java
package com.zetcode;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Toolkit;
import javax.swing.ImageIcon;
import javax.swing.JPanel;
public class Board extends JPanel
implements Runnable {
private final int B_WIDTH = 350;
private final int B_HEIGHT = 350;
private final int INITIAL_X = -40;
private final int INITIAL_Y = -40;
private final int DELAY = 25;
private Image star;
private Thread animator;
private int x, y;
public Board() {
initBoard();
}
private void loadImage() {
ImageIcon ii = new ImageIcon("star.png");
star = ii.getImage();
}
private void initBoard() {
setBackground(Color.BLACK);
setPreferredSize(new Dimension(B_WIDTH, B_HEIGHT));
setDoubleBuffered(true);
loadImage();
x = INITIAL_X;
y = INITIAL_Y;
}
#Override
public void addNotify() {
super.addNotify();
animator = new Thread(this);
animator.start();
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
drawStar(g);
}
private void drawStar(Graphics g) {
g.drawImage(star, x, y, this);
Toolkit.getDefaultToolkit().sync();
}
private void cycle() {
x += 1;
y += 1;
if (y > B_HEIGHT) {
y = INITIAL_Y;
x = INITIAL_X;
}
}
#Override
public void run() {
long beforeTime, timeDiff, sleep;
beforeTime = System.currentTimeMillis();
while (true) {
cycle();
repaint();
timeDiff = System.currentTimeMillis() - beforeTime;
sleep = DELAY - timeDiff;
if (sleep < 0) {
sleep = 2;
}
try {
Thread.sleep(sleep);
} catch (InterruptedException e) {
System.out.println("Interrupted: " + e.getMessage());
}
beforeTime = System.currentTimeMillis();
}
}
}
When I run the program, I get a blank black window. The program is supposed to draw a star. Here is what it is supposed to look like.

Game Applet not running in 2D game (while loop)

I'm trying to set the dimensions for this game i want to create. The error is at while(running); I went over it for an hour but i can't seem to catch the error. I'm using NetbeansIDE also setPreserredSize (new Dimension(WIDTH, HEIGHT)); gives me an error, it is asking to Create a method " setPrefferedSize(java.awt.Dimension)"in.com.francesc.game.Game
private void setPreserredSize(Dimension dimension) {
throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
when i run it i get this error
Exception in thread "main" java.lang.RuntimeException: Uncompilable source code - illegal start of type
at com.francescstudio.game.Game.<init>(Game.java:67)
at com.francescstudio.game.Start.main(Start.java:16)
Java Result: 1
heres all the code
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.image.BufferedImage;
import javax.swing.JPanel;
/**
*
* #author francesc
*/
public class Game extends JPanel implements KeyListener, Runnable {
public static final long SerialVersionUID = 1L;
public static final int WIDTH = 400;
public static final int HEIGHT = 630;
public static final Font main = new Font("Bebas Nue Regular", Font.PLAIN, 28);
private Thread game;
private boolean running;
private BufferedImage Image = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
private long startTime;
private long elapse;
private boolean set;
public Game() {
setFocusable(true);
setPreserredSize (new Dimension(WIDTH, HEIGHT));
addKeyListener(this);
}
private void update() {
}
private void render() {
Graphics2D g = (Graphics2D) Image.getGraphics();
g.setColor(Color.white);
g.fillRect(0, 0, WIDTH, HEIGHT);
// render board
g.dispose();
Graphics2D g2d = (Graphics2D) getGraphics();
g2d.drawImage(Image, 0, 0, null);
g2d.dispose();
}
#Override
public void run() {
}
int fps = 0, update = 0;
long fpsTimer = System.currentTimeMillis();
double nsPerUpdate = 1000000000.0 / 60;
// last update time in nano seconds
double then = System.nanoTime();
double unprocessed = 0;
while (running){
boolean shouldRender = false;
double now = System.nanoTime();
unprocessed += (now - then) / nsPerUpdate;
then = now;
// update queque
while (unprocessed >= 1) {
update++;
update();
unprocessed--;
shouldRender = true;
}
// render
if (shouldRender) {
fps++;
render();
shouldRender = false;
} else {
try {
Thread.sleep(1);
} catch (Exception e) {
e.printStackTrace();
}
}
}
public synchronized start(){
if(running)return;
running = true;
game = new Thread (this, "game");
game.start();
}
public synchronized stop (){
if(!running) return;
running = false;
System.exit(0);
}
#Override
public void keyTyped(KeyEvent e) {
}
#Override
public void keyPressed(KeyEvent e) {
}
#Override
public void keyReleased(KeyEvent e) {
}
}

Your problem is while (running) {} isn't inside of a method, you defined it in the class where it will never get called.
EDIT:
Your code should look something a little more like this
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.image.BufferedImage;
import javax.swing.JPanel;
/**
*
* #author francesc
*/
public class Game extends JPanel implements KeyListener, Runnable {
public static final long SerialVersionUID = 1L;
public static final int WIDTH = 400;
public static final int HEIGHT = 630;
public static final Font main = new Font("Bebas Nue Regular", Font.PLAIN, 28);
private Thread game;
private boolean running;
private BufferedImage Image = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
private long startTime;
private long elapse;
private boolean set;
public Game() {
setFocusable(true);
setPreferredSize(new Dimension(WIDTH, HEIGHT));
addKeyListener(this);
}
private void update() {}
private void render() {
Graphics2D g = (Graphics2D) Image.getGraphics();
g.setColor(Color.white);
g.fillRect(0, 0, WIDTH, HEIGHT);
// render board
g.dispose();
Graphics2D g2d = (Graphics2D) getGraphics();
g2d.drawImage(Image, 0, 0, null);
g2d.dispose();
}
#Override
public void run() {
int fps = 0, update = 0;
long fpsTimer = System.currentTimeMillis();
double nsPerUpdate = 1000000000.0 / 60;
// last update time in nano seconds
double then = System.nanoTime();
double unprocessed = 0;
while (running) {
boolean shouldRender = false;
double now = System.nanoTime();
unprocessed += (now - then) / nsPerUpdate;
then = now;
// update queque
while (unprocessed >= 1) {
update++;
update();
unprocessed--;
shouldRender = true;
}
// render
if (shouldRender) {
fps++;
render();
shouldRender = false;
} else {
try {
Thread.sleep(1);
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
public synchronized start(){
if(running)return;
running = true;
game = new Thread (this, "game");
game.start();
}
public synchronized stop (){
if(!running) return;
running = false;
System.exit(0);
}
#Override
public void keyTyped(KeyEvent e) {
}
#Override
public void keyPressed(KeyEvent e) {
}
#Override
public void keyReleased(KeyEvent e) {
}
}

java graphics isn't drawing anything

The program draws a bunch of rectangles for a bar graph. I know the bar class works perfectly fine because I've got it working before adding in the graph panel class. I was drawing straight onto the frame instead of the graph panel. I assume its a problem in the way my set visible methods are called as it was pointed out to me before. I tried looking into it but I've had no luck after playing around and reading documentation.
import java.awt.Color;
import java.util.ArrayList;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.util.concurrent.Semaphore;
#SuppressWarnings("serial")
public class GraphPanel extends JPanel {
private ArrayList<Bar> graphBars;
private int nBars;
public GraphPanel(int nBars, JFrame mainFrame) {
this.setSize(400, 400);
this.graphBars = new ArrayList<Bar>(nBars);
this.nBars = nBars;
this.initBars(mainFrame.getWidth());
for(Bar b: this.graphBars) {
this.add(b);
}
}
private void initBars(int frameW) {
Random random = new Random();
float hue;
Color color;
int barPadding = frameW/this.nBars;
for(int i = 0; i < this.nBars; i++) {
hue = random.nextFloat();
color = Color.getHSBColor(hue, 0.9f, 1.0f);
this.graphBars.add(new Bar(i*barPadding + 30, 350, color));
}
}
public ArrayList<Bar> getBarList() {
return this.graphBars;
}
}
#SuppressWarnings("serial")
public class Bar extends JPanel implements Runnable {
int height = 0;
Color barColor;
Rectangle bar;
private final int WIDTH = 20;
Thread bartender;
private Semaphore s;
public Bar(int x, int y, Color barColor) {
this.barColor= barColor;
this.bar = new Rectangle(x, y, this.WIDTH, this.height);
this.bartender= new Thread(this);
this.s = new Semaphore(1);
}
public boolean setNewHeight(int h) {
try {
this.s.acquire();
this.height = h;
this.s.release();
return true;
} catch (InterruptedException e) {
e.printStackTrace();
return false;
}
}
#SuppressWarnings("deprecation")
public void update() {
if (this.bar.height < this.height) {
bar.reshape(this.bar.x, --this.bar.y, this.bar.width, ++this.bar.height);
} else {
bar.reshape(this.bar.x, ++this.bar.y, this.bar.width, --this.bar.height);
}
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setColor(this.barColor);
g2d.fill(this.bar);
}
#SuppressWarnings("deprecation")
public void callBarTender() {
this.bartender.resume();
}
#SuppressWarnings("deprecation")
#Override
public void run() {
System.out.println("sdf");
while(true) {
if (this.bar.height < this.height) {
for(int i = this.bar.height; i<this.height; i++ ) {
try {
update();
repaint();
Thread.sleep(15);
} catch(Exception e) {
System.out.println(e);
}
}
} else if (this.height < this.bar.height) {
for(int i = this.bar.height; i>this.height; i-- ) {
try {
update();
repaint();
Thread.sleep(15);
} catch(Exception e) {
System.out.println(e);
}
}
}
this.bartender.suspend();
}
}
}
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.setSize(400, 400);
frame.setResizable(false);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
GraphPanel gPane = new GraphPanel(3, frame);
frame.add(gPane);
gPane.getBarList().get(0).setVisible(true);
gPane.getBarList().get(1).setVisible(true);
gPane.getBarList().get(2).setVisible(true);
gPane.setVisible(true);
frame.setVisible(true);
gPane.getBarList().get(0).setNewHeight(100);
gPane.getBarList().get(1).setNewHeight(100);
gPane.getBarList().get(2).setNewHeight(100);
gPane.getBarList().get(0).bartender.start();
gPane.getBarList().get(1).bartender.start();
gPane.getBarList().get(2).bartender.start();
}

You should override getPreferredSize of your GraphPanel to ensure that they are laid out correctly
The x/y positions you are passing to the Bar class are irrelevant, as this is causing your Rectangle to paint outside of the visible context of the Bar pane. Painting is done from within the context of the component (0x0 been the top/left corner of the component)
The use of Rectangle or the way you are using it, is actually causing issues. It's impossible to know exactly how big you component will be until it's layed or painted
There is a reason why resume and suspend are deprecated, this could cause no end of "weird" (and wonderful) issues
Take a look at Laying Out Components Within a Container for why you're bars aren't been updated correctly and why the x/y coordinates are pointless
Take a look at How to use Swing Timers for an alternative to your use of Thread
Possibly, something more like...
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.LineBorder;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame();
frame.setSize(400, 400);
// frame.setResizable(false);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
GraphPanel gPane = new GraphPanel(3, frame);
frame.add(gPane);
gPane.getBarList().get(1).setFill(false);
gPane.getBarList().get(0).start();
gPane.getBarList().get(1).start();
gPane.getBarList().get(2).start();
frame.setVisible(true);
}
});
}
public class GraphPanel extends JPanel {
private ArrayList<Bar> graphBars;
private int nBars;
public GraphPanel(int nBars, JFrame mainFrame) {
this.graphBars = new ArrayList<Bar>(nBars);
this.nBars = nBars;
this.initBars(mainFrame.getWidth());
for (Bar b : this.graphBars) {
this.add(b);
}
}
private void initBars(int frameW) {
Random random = new Random();
float hue;
Color color;
for (int i = 0; i < this.nBars; i++) {
hue = random.nextFloat();
color = Color.getHSBColor(hue, 0.9f, 1.0f);
this.graphBars.add(new Bar(color));
}
}
public ArrayList<Bar> getBarList() {
return this.graphBars;
}
}
#SuppressWarnings("serial")
public class Bar extends JPanel {
private Color barColor;
private boolean fill = true;
private float fillAmount = 0;
private float delta = 0.01f;
private Timer timer;
private Rectangle bar;
public Bar(Color barColor) {
bar = new Rectangle();
setBorder(new LineBorder(Color.RED));
this.barColor = barColor;
timer = new Timer(15, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
fillAmount += isFill() ? delta : -delta;
// System.out.println(fillAmount);
if (fillAmount < 0) {
fillAmount = 0;
((Timer) e.getSource()).stop();
} else if (fillAmount > 1.0f) {
fillAmount = 1f;
((Timer) e.getSource()).stop();
}
repaint();
}
});
}
public void start() {
timer.start();
}
public void stop() {
timer.stop();
}
public void setFill(boolean fill) {
this.fill = fill;
if (!timer.isRunning()) {
if (fill && fillAmount == 1) {
fillAmount = 0;
} else if (!fill && fillAmount == 0) {
fillAmount = 1;
}
}
}
public boolean isFill() {
return fill;
}
#Override
public Dimension getPreferredSize() {
return new Dimension(20, 100);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setColor(this.barColor);
int height = Math.round(getHeight() * fillAmount);
bar.setSize(getWidth(), height);
bar.setLocation(0, getHeight() - height);
g2d.fill(bar);
g2d.dispose();
}
}
}

Java game won't read image file

For some reason, my program can't find an image. I've tried absolutely everything and made sure the file path is exact. It worked fine in my previous game but now it just won't find the image at all.
Entity class
package Entities;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import javax.imageio.ImageIO;
public class Entity
{
public double x, y, width, height, dx, dy;
public BufferedImage image;
public Entity(String s)
{
try
{ //error occurs here
image = ImageIO.read(getClass().getResourceAsStream(s));
}
catch (IOException e)
{
e.printStackTrace();
}
width = image.getWidth();
height = image.getHeight();
}
public void update()
{
x += dx;
y += dy;
}
public void draw(Graphics2D g)
{
g.drawImage(image, (int)x, (int)y, null);
}
}
GamePanel class
package Main;
//import java.awt.Container;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.image.BufferedImage;
import javax.swing.JPanel;
import Entities.Entity;
#SuppressWarnings("serial")
public class GamePanel extends JPanel implements Runnable, KeyListener
{
public static final int WIDTH = 320;
public static final int HEIGHT = 240;
public static final int SCALE = 2;
//game thread
private Thread thread;
private boolean running;
private int fps = 60;
private long targetTime = 1000/fps;
//image
private BufferedImage image;
private Graphics2D g;
//test
public Entity e;
public GamePanel()
{
super();
setPreferredSize(new Dimension(WIDTH * SCALE, HEIGHT * SCALE));
setFocusable(true);
requestFocus();
}
public void addNotify()
{
super.addNotify();
if(thread == null)
{
thread = new Thread(this);
addKeyListener(this);
thread.start();
}
}
public void init()
{
image = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
g = (Graphics2D) image.getGraphics();
running = true;
e = new Entity("Resources/Test/test.png");
}
#Override
public void keyPressed(KeyEvent key)
{
//p1.keyPressed(key.getKeyCode());
}
#Override
public void keyReleased(KeyEvent key)
{
//p1.keyReleased(key.getKeyCode());
}
#Override
public void keyTyped(KeyEvent arg0)
{
}
#Override
public void run()
{
init();
long start;
long elapsed;
long wait;
//game loop
while(running)
{
start = System.nanoTime();
update();
draw();
drawToScreen();
elapsed = System.nanoTime() - start;
wait = targetTime - elapsed/1000000;
if(wait < 0)
{
wait = 5;
}
try
{
Thread.sleep(wait);
}
catch(Exception e)
{
e.printStackTrace();
}
}
}
private void drawToScreen()
{
Graphics g2 = getGraphics();
g2.drawImage(image, 0, 0, WIDTH * SCALE, HEIGHT * SCALE, null);
g2.dispose();
}
private void draw()
{
//e.draw(g);
}
private void update()
{
}
}
This is the error
Exception in thread "Thread-2" java.lang.IllegalArgumentException: input == null!
at javax.imageio.ImageIO.read(Unknown Source)
at Entities.Entity.<init>(Entity.java:19)
at Main.GamePanel.init(GamePanel.java:67)
at Main.GamePanel.run(GamePanel.java:93)
at java.lang.Thread.run(Unknown Source)

A path Resources/Test/test.png suggest a relative path from the location of the class reference used to try and load it.
Since you are using your Entity class to try and load the image, and Entity resides in the Entities package, this will generate an absolute path (from the context of the class path) of /Entities/Resources/Test/test.png, which is obviously incorrect.
Try using /Resources/Test/test.png instead (assuming the Resources resides at the top of the path tree, for example...
+ Resources
+ Test
- test.png
+ Entities
- Entity
+ Main
- GamePanel