java - Why won't my avatar move. -

this code. box not move if click directional key. so, want know what's going on. can me? in advance!

import java.awt.*; import javax.swing.*;       import java.applet.*; import java.awt.event.*; import java.awt.robot.*; import java.awt.color.*; public class project extends applet implements mouselistener, mousemotionlistener, keylistener {    robot robos;    color colour;    string s = "";    int mousex = 0, mousey = 0;    int width, height;    int x, y;    int bsx, bsy;    int blsx, blsy;    int lto, ltt, rto, rtt;     boolean canpass;    public void init(){     canpass = true;     colour = new color(0, 0, 0);     addmouselistener(this);     addmousemotionlistener(this);     addkeylistener(this);     width = getsize().width;     height = getsize().height;     bsx = width / 2 - 3;     bsy = height / 2 - 3;     blsx = width / 2 - 2;     blsy = height / 2 - 2;     repaint();     lto = height;     ltt = (width / 2)/ 2;     rto = height;     rtt = (int)((double)((width / 2) * 1.5)); } public void mouseclicked(mouseevent me){     x = me.getx();     y = me.gety();               //this method has no relevance problem.     s = "";     repaint();     me.consume();     }     public void mouseentered(mouseevent me){ }     public void mouseexited(mouseevent me){ }     public void mousepressed(mouseevent me){ }     public void mousereleased(mouseevent me){ }     public void mousedragged(mouseevent me){ }     public void keypressed( keyevent me ) {   //this method want at(and paint too)         if((me.getkeycode() == keyevent.vk_down || me.getkeycode() == keyevent.vk_kp_down) && (bsy + 10 <= height)){              for(int = bsx; < bsx + 5; a++){                 colour = robos.getpixelcolor(a, bsy + 6);                                    if(colour.equals(color.black)){                      canpass = false;                                     }             }             if(canpass){                  bsy++;                  blsy++;             }                 }                          if(me.getkeycode() == keyevent.vk_up || me.getkeycode() == keyevent.vk_kp_up){               for(int = bsx; < bsx + 5; a++){                   colour = robos.getpixelcolor(a, bsy - 1);                  if(colour.equals(color.black)){                     canpass = false;                  }               }              if(canpass){               bsy--;               blsy--;              }         }         if(me.getkeycode() == keyevent.vk_left || me.getkeycode() == keyevent.vk_kp_left){              for(int = bsy + 6; > bsy; a--){                       colour = robos.getpixelcolor(bsx - 1, a);                     if(colour.equals(color.black)){                         canpass = false;                     }              }              if(canpass){                  bsx--;                  blsx--;              }           }         if(me.getkeycode() == keyevent.vk_right || me.getkeycode() == keyevent.vk_kp_right){             for(int = bsy + 6; < bsy + 11; a++){                      colour = robos.getpixelcolor(bsx + 6, a);                     if(colour.equals(color.black)){                         canpass = false;                     }             }             if(canpass){                 bsx++;                 blsx++;             }         }         repaint();         me.consume();         canpass = true;     }     public void keyreleased( keyevent me ) { }     public void keytyped( keyevent me ) { }     public void mousemoved(mouseevent me){         showstatus("moving mouse @ " + me.getx() + ", " + me.gety());     }     public void paint(graphics g){          g.drawline(ltt, lto, ltt, 0);         g.drawline(rtt, rto, rtt, 0);         g.setcolor(color.cyan);         g.drawrect(bsx, bsy, 5, 5);         g.setcolor(color.blue);         g.fillrect(blsx, blsy, 4, 4);         g.setcolor(color.black);         g.drawline(0, 400, 500, 400);     } } 

if possible, can have explanation of what's going wrong know avoid in future when code? once again in advance!