java - My drawn object doesn't clear previous rectangle after key is pressed -

my code not clear previous rectangle when press 1 of arrow keys. thought using repaint() in keypressed() method, solve problem. tried using clearrect(), doesn't anything.

this idle rectangle:

this when hold down right arrow key:

here code:

import java.awt.component; import java.awt.dimension; import java.awt.graphics; import java.awt.graphics2d; import java.awt.event.keyevent; import java.awt.geom.rectangle2d;  import javax.swing.icon;  import java.awt.*; import java.awt.event.keyevent; import java.awt.event.keylistener; import java.awt.geom.affinetransform; import java.awt.geom.arc2d; import java.awt.geom.pathiterator; import java.awt.geom.point2d; import java.awt.geom.rectangle2d; import java.util.arraylist;  import javax.swing.icon; import javax.swing.jcomponent; import javax.swing.jframe; import javax.swing.jlabel; import javax.swing.joptionpane; import javax.swing.jpanel;   public class rectangle extends jpanel implements keylistener{  private int height; private int width; private int x; private int y; private graphics2d g2;    public rectangle(int width, int height,int x, int y) {     this.height = height;     this.width = width;     this.x = x;     this.y = y;      jlabel label = new jlabel();     label.addkeylistener(this);     label.setfocusable(true);     label.setopaque(true);     label.addkeylistener(this);     this.add(label);     label.requestfocusinwindow();     setvisible(true);  }  public dimension getpreferredsize() {         return new dimension(500,500);     }  public void keypressed(keyevent e) {         if (e.getkeycode() == keyevent.vk_down)     {         y = y + 5;         repaint();     }     if (e.getkeycode() == keyevent.vk_left)     {         x = x - 5;         repaint();     }     if (e.getkeycode() == keyevent.vk_up)     {         y = y - 5;         repaint();     }      if (e.getkeycode() == keyevent.vk_right)     {         x = x + 5;         repaint();     }  }   public void keyreleased(keyevent e) {}  public void keytyped(keyevent e) {}     public void paintcomponent(graphics g) {  this.g2 = (graphics2d) g; g2.drawrect(x, y, width, height);  }  }  

test class

import java.awt.dimension; import java.awt.flowlayout;  import javax.swing.jframe; import javax.swing.jlabel; import javax.swing.jpanel; import javax.swing.swingutilities;       public class test {   public static void main(string[] args) {         swingutilities.invokelater(new runnable() {             public void run() {                 createandshowgui();              }         });     }      private static void createandshowgui() {          jframe f = new jframe("rectangle");         f.setdefaultcloseoperation(jframe.exit_on_close);         f.add( new rectangle(40,20,250,250));         f.pack();         f.setvisible(true);      }  } 

you have missed add super.paintcomponent(g); breaking flow.

this working fine code making single line changes.

public void paintcomponent(graphics g) {     super.paintcomponent(g); // add line      this.g2 = (graphics2d) g;     g2.drawrect(x, y, width, height);  } 

please read more painting in awt , swing