swing - Draw in java like windows paint -

i made java app draw, windows paint, not know if it's better in 2 classes, or left unattended in class, , on other side. can make more efficient?

here code:

    import java.awt.graphics;     import java.awt.*;     import java.awt.event.*;     import javax.swing.*;      public class mypaint{         public static void main(string[] args){           jframe frame = new jframe("just paint");          container content = frame.getcontentpane();      content.setlayout(new borderlayout());            final paddraw drawpad = new paddraw();            content.add(drawpad, borderlayout.center);       jpanel panel = new jpanel();      panel.setpreferredsize(new dimension(100, 68));     panel.setminimumsize(new dimension(100, 68));     panel.setmaximumsize(new dimension(100, 68));              jbutton twox = new jbutton ("2");             twox.addactionlistener(new actionlistener(){                  public void actionperformed(actionevent e){             drawpad.clear();         }     });                    jbutton yellowbutton = new jbutton("yellow");     yellowbutton.setforeground(new color(204, 204, 0));      yellowbutton.addactionlistener(new actionlistener(){         public void actionperformed(actionevent e){             drawpad.yellow();         }      });       jbutton greenbutton = new jbutton("green");     greenbutton.setforeground(new color(0, 204, 0));      greenbutton.addactionlistener(new actionlistener(){         public void actionperformed(actionevent e){             drawpad.green();         }     });      jbutton redbutton = new jbutton("red");     redbutton.setforeground(new color(255, 0, 0));      redbutton.addactionlistener(new actionlistener(){         public void actionperformed(actionevent e){             drawpad.red();         }     });      jbutton bluebutton = new jbutton("blue");     bluebutton.setforeground(color.blue);      bluebutton.addactionlistener(new actionlistener(){         public void actionperformed(actionevent e){             drawpad.blue();         }     });      jbutton blackbutton = new jbutton("black");      blackbutton.addactionlistener(new actionlistener(){         public void actionperformed(actionevent e){             drawpad.black();         }     });     greenbutton.setpreferredsize(new dimension(80, 20));     redbutton.setpreferredsize(new dimension(80, 20));     yellowbutton.setpreferredsize(new dimension(80, 20));     bluebutton.setpreferredsize(new dimension(80, 20));     greenbutton.setpreferredsize(new dimension(80,20));       panel.add(blackbutton);     panel.add(bluebutton);     panel.add(redbutton);     panel.add(greenbutton);     panel.add(yellowbutton);       content.add(panel, borderlayout.north);      jradiobutton rdbtnpx = new jradiobutton("3 px");     panel.add(rdbtnpx);      jradiobutton rdbtnpx_1 = new jradiobutton("5 px");     panel.add(rdbtnpx_1);      jradiobutton rdbtnpx_2 = new jradiobutton("12 px");     panel.add(rdbtnpx_2);       buttongroup bg = new buttongroup();     bg.add(rdbtnpx);     bg.add(rdbtnpx_1);     bg.add(rdbtnpx_2);      rdbtnpx.addactionlistener(new actionlistener(){         public void actionperformed(actionevent e){             drawpad.small();         }     });     rdbtnpx_1.addactionlistener(new actionlistener(){         public void actionperformed(actionevent e){             drawpad.medium();         }     });     rdbtnpx_2.addactionlistener(new actionlistener(){         public void actionperformed(actionevent e){             drawpad.big();         }     });      jbutton clearbutton = new jbutton("clear");     clearbutton.setbackground(new color(255, 255, 255));     clearbutton.setfont(uimanager.getfont("textarea.font"));      clearbutton.addactionlistener(new actionlistener(){         public void actionperformed(actionevent e){             drawpad.clear();         }     });     panel.add(clearbutton);      frame.setsize(454, 440);      frame.setdefaultcloseoperation(jframe.exit_on_close);      frame.setvisible(true);  } }   class paddraw extends jcomponent{  private image image;     private graphics2d graphics2d;   private int currentx , currenty , oldx , oldy ;  public paddraw(){     setdoublebuffered(false);     addmouselistener(new mouseadapter(){         public void mousepressed(mouseevent e){             oldx = e.getx();             oldy = e.gety();         }     });      addmousemotionlistener(new mousemotionadapter(){         public void mousedragged(mouseevent e){             currentx = e.getx();             currenty = e.gety();             if(graphics2d != null)             graphics2d.drawline(oldx, oldy, currentx, currenty);             repaint();             oldx = currentx;             oldy = currenty;         }      });  }     public void paintcomponent(graphics g){     if(image == null){         image = createimage(getsize().width, getsize().height);         graphics2d = (graphics2d)image.getgraphics();         graphics2d.setrenderinghint(renderinghints.key_antialiasing, renderinghints.value_antialias_on);         clear();      }     g.drawimage(image, 5, 5, null); }  public void clear(){     graphics2d.setpaint(color.white);     graphics2d.fillrect(0, 0, getsize().width, getsize().height);     graphics2d.setpaint(color.black);     repaint(); }  public void red(){     graphics2d.setpaint(color.red);     repaint(); }  public void black(){     graphics2d.setpaint(color.black);     repaint(); }  public void yellow(){     graphics2d.setpaint(color.yellow);     repaint(); }  public void blue(){     graphics2d.setpaint(color.blue);     repaint(); }  public void green(){     graphics2d.setpaint(color.green);     repaint(); } public void small(){     graphics2d.setstroke(new basicstroke(1));; } public void medium(){     graphics2d.setstroke(new basicstroke(5));; } public void big(){     graphics2d.setstroke(new basicstroke(12));; }  } 

try follow single responsibility principle.

it means class should change 1 reason.

keeping code wrote in 1 class breaking principle. split in different classes each 1 doing 1 thing.