Problem on drawin a graph

Question

I'm a just beginner in Swing.I want to draw a graph on a frame.My problem is.....:in the o/p window graph is just become disable afterit came.it will reappear whwn we maximize thhe o/p window...my part of code is following:
public void paint(Graphics g) {//main graph drawing part
          super.paint(g);
          Graphics2D g2 = (Graphics2D)g;
          g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
          for(i=0;i<ss2;i++){//assigning the the values of FROM node and TO node
               pf=p[Integer.parseInt(str2[i][0])];
               pt[i]=p[Integer.parseInt(str2[i][2])];
          for(i=0;i<ss2;i++){//to print the value like a,b,c...
               xf=pf[i].x;
               yf=pf[i].y;
               xt=pt[i].x;
               yt=pt[i].y;
               xm=(xf+xt*3)/4;
               ym=((yf+yt*3)/4)-5;
               sssss=str2[i][1].charAt(0);
               g2.setColor(Color.black);
               if(xf==xt&&yf==yt){
                    g2.drawArc(xf,yf,35,20,0,360);
                    g2.drawString(Character.toString(sssss),xf+15,yf+12);
               else{
                    g2.drawLine(xf,yf,xt,yt);
                    g2.setColor(Color.black);
                    g2.drawString(Character.toString(sssss),xm,ym);
                    g2.fillOval(m,n,7,7);
          for(i=0;i<sc1;i++) {//for loop to draw the circle class to draw circles
               int _x;
               int _y;
               _x=(p[i].x-10);
               _y=(p[i].y-10);
               if(str1[i][3].equals("1")){
               g2.setColor(Color.PINK);
               g2.fillOval(_x, _y,20,20);
               x=0;y=0;
          else if(str1[i][3].equals("2")){
               g2.setColor(Color.CYAN);
               g2.fillOval(_x, y,20,20);x=0;_y=0;
          else if(str1[i][3].equals("4")){
               g2.setColor(Color.YELLOW);
               g2.fillOval(_x, y,20,20);x=0;_y=0;
          else{
               g2.setColor(Color.ORANGE);
               g2.fillOval(_x, y,20,20);x=0;_y=0;
          for(i=0;i<sc1;i++){//to put the node name like 1,2...i'll changed it to Q0,Q1,... later
               g2.setColor(Color.BLACK);
               g2.drawString(Integer.toString(i),p[i].x,p[i].y);

Answer 1

Comments:
If you had gone through the painting tutorial linked, you would know that custom painting is not normally performed on a JFrame. And knowing that, you would find no reason to extend JFrame.
If you had taken a look at the API you would know that JFrame doesn't have a method paintComponent.
If you had gone through the Swing tutorial linked, you would know about concurrency in Swing, and that the GUI should be launched on the EDT.
So. With the wealth of knowledge already available in the tutorials, do you really think forum members should waste their time teaching you the basics? Please go through the changed code and post back what you conclude about the differences that make it work.
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class FrameTest {
   int px, py, ox, oy;
   JFrame frame;
   JPanel panel;
   FrameTest(String title, int x1, int y1, int x2, int y2){
      frame = new JFrame(title);
      px = x1;
      py = y1;
      ox = x2;
      oy = y2;
   private void makeUI() {
      panel = new JPanel() {
         public void paintComponent(Graphics g){
            super.paintComponent(g);
            g.drawLine(px, py, ox, oy);
      frame.setContentPane(panel);
      frame.setSize(300, 300);
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.setVisible(true);
   public static void main(String args[]) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            new FrameTest("Show", 10, 10, 100, 100).makeUI();
}db