Draw circles in swing..

Question

hello.
I'm making a program that draws circles in a frame and has some buttons in another program.
However, there are some stack overflow errors..
help please~
[error messages]
Exception in thread "main" java.lang.StackOverflowError
at java.util.Hashtable.get(Hashtable.java:336)
at javax.swing.UIDefaults.getFromHashtable(UIDefaults.java:142)
at javax.swing.UIDefaults.get(UIDefaults.java:130)
at javax.swing.MultiUIDefaults.get(MultiUIDefaults.java:44)
at javax.swing.UIDefaults.getColor(UIDefaults.java:380)
at javax.swing.UIManager.getColor(UIManager.java:590)
at javax.swing.LookAndFeel.installColors(LookAndFeel.java:58)
at javax.swing.LookAndFeel.installColorsAndFont(LookAndFeel.java:92)
at javax.swing.plaf.basic.BasicPanelUI.installDefaults(BasicPanelUI.java:49)
at javax.swing.plaf.basic.BasicPanelUI.installUI(BasicPanelUI.java:39)
at javax.swing.JComponent.setUI(JComponent.java:652)
at javax.swing.JPanel.setUI(JPanel.java:131)
at javax.swing.JPanel.updateUI(JPanel.java:104)
at javax.swing.JPanel.<init>(JPanel.java:64)
at javax.swing.JPanel.<init>(JPanel.java:87)
at javax.swing.JPanel.<init>(JPanel.java:95)
at DrawCircle.<init>(DrawCircle.java:7)
at DrawCircle.<init>(DrawCircle.java:6)
import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
public class GUI{
     DrawCircle circle = new DrawCircle(100,100,50);
     private JButton UpButton, DownButton, LeftButton, RightButton, IncreaseButton, DecreaseButton, InputButton;
     public void drawframe(){
                final JFrame CircleFrame = new JFrame("Frame for Circle");
                CircleFrame.getContentPane().add(circle);
                CircleFrame.setSize(200,200);
          CircleFrame.setVisible(true);
          UpButton = new JButton("UP");
          UpButton.addActionListener(new ActionListener()     {
               public void actionPerformed(ActionEvent e){
                            circle.up();
                                if(circle.getY() - circle.getR() <= 0) {
                                    JOptionPane.showMessageDialog( CircleFrame, "Out of window");
                                    circle.setY(circle.getY() +10);
          RightButton = new JButton("RIGHT");
          RightButton.addActionListener(new ActionListener()     {
               public void actionPerformed(ActionEvent e)     {
                            circle.right();
                                if(circle.getX() + circle.getR() >= 500) {
                                    JOptionPane.showMessageDialog( CircleFrame, "Out of window");
                                    circle.setX(circle.getX() -10);
          LeftButton = new JButton("LEFT");
          LeftButton.addActionListener(new ActionListener(){
               public void actionPerformed(ActionEvent e){
                            circle.left();
                                if(circle.getX() - circle.getR() <= 0) {
                                    JOptionPane.showMessageDialog( CircleFrame, "Out of window");
                                    circle.setX(circle.getX() +10);
          DownButton = new JButton("DOWN");
          DownButton.addActionListener(new ActionListener(){
               public void actionPerformed(ActionEvent e){
                            circle.down();
                                System.out.println(circle.getY());
                                if(circle.getY() + circle.getR() >= 500) {
                                    JOptionPane.showMessageDialog( CircleFrame, "Out of window");
                                    circle.setY(circle.getY() -10);
          IncreaseButton = new JButton("INCREASE");
          IncreaseButton.addActionListener(new ActionListener()     {
               public void actionPerformed(ActionEvent e)     {
                            circle.increase();
                                if(circle.getY() + circle.getR() >= 500) {
                                    JOptionPane.showMessageDialog( CircleFrame, "Out of window");
                                    circle.setR(circle.getR() -10);     
                                } else if(circle.getX() + circle.getR() >= 500) {
                                    JOptionPane.showMessageDialog( CircleFrame, "Out of window");
          DecreaseButton = new JButton("decrease");
                    DecreaseButton.addActionListener(new ActionListener(){
                            public void actionPerformed(ActionEvent e)     {           
                                circle.decrease();
          JPanel ButtonPanel = new JPanel();
          ButtonPanel.add(IncreaseButton);
          ButtonPanel.add(DecreaseButton);
          ButtonPanel.add(DownButton);
          ButtonPanel.add(LeftButton);
          ButtonPanel.add(RightButton);
          ButtonPanel.add(UpButton);
          ButtonPanel.setLayout(new BoxLayout(ButtonPanel, BoxLayout.Y_AXIS));
                JFrame mainFrame = new JFrame("GUI for Circle Drawing");
          mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE );
                mainFrame.add(ButtonPanel);
                mainFrame.pack();
          mainFrame.setVisible(true);
     public static void main(String [] args)     {
          GUI intf = new GUI();
          intf.drawframe();
}and the DrawCircle Class is
import java.awt.*;
import javax.swing.*;
public class DrawCircle extends JPanel{
     private int x, y, r;
        DrawCircle circle = new DrawCircle(100, 100, 50);
     public DrawCircle( int x , int y , int r){
          this.x = x;
          this.y = y;
          this.r = r;
     public int getR(){
          return r;
     public int getX(){
          return x;
     public int getY(){
          return y;
     public void setX(int x)     {
          this.x = x;
                repaint();
     public void setY(int y)     {
          this.y = y;
                repaint();
     public void setR(int r)     {
          this.r = r;
                repaint();
     public void paint(Graphics g){
          g.clearRect(0,0,400,400);
                g.drawOval(x-r, y-r, r*2, r*2);
        public void up() {
          circle.setY(circle.getY() -10);
        public void down() {
                circle.setY(circle.getY() +10);
        public void right() {
                circle.setX(circle.getX() +10);
        public void left() {
                circle.setX(circle.getX() -10);
        public void increase() {
                circle.setR(circle.getR() +10);     
        public void decrease() {
                circle.setR(circle.getR() -10);     
          

Answer 1

The problem is that you're constructing a new DrawCircle each time you construct a new DrawCircle, resulting in infinite recursion causing a stack overflow.
This line:DrawCircle circle = new DrawCircle(100, 100, 50);in your DrawCircle class is causing the problem, do you need it? Remove it and replace references to 'circle' in the class with 'this'.