3. Hello MIDlet

import javax.microedition.lcdui.*; 
import javax.microedition.midlet.*; 

public class Test1 extends MIDlet{
    //###############################################################################################
    //# MIDlet 클래스 추상 메소드
    //# [MIDlet 생명주기 1] 응용프로그램이 시작 될 때.
    //# canvas 클래스의 쓰레드가 live인 동안 응용프로그램은 Activate 상태이다.
    //###############################################################################################
    public void startApp(){ 
        Display display=    Display.getDisplay(this);        //현재 MIDlet에 해당하는 Display 객체를 얻는다.
        Canvas  canvas=     new testCanvas();                //Canvas 인스턴스 생성.
        
        display.setCurrent(canvas);                          //파라미터(canvas)를 display한다.
    }

    //###############################################################################################
    //# MIDlet 클래스 추상 메소드 정의
    //# [MIDlet 생명주기 2] 전화가 왔을 때와 같은 MIDlet 사용 불가 상태.
    //###############################################################################################
    public void pauseApp(){}

    //###############################################################################################
    //# MIDlet 클래스 추상 메소드
    //# [MIDlet 생명주기 3] 종료될 때.
    //###############################################################################################
    public void destroyApp(boolean b){}
}

class testCanvas extends Canvas{
    //###############################################################################################
    //# Canvas 클래스의 추상 메소드 정의
    //###############################################################################################
    public void paint(Graphics g){
        g.setColor(0x000000);
        g.drawString("Hello MIDlet", this.getWidth()/2, this.getHeight()/2, g.TOP | g.LEFT);
    }
}


Display 객체는 액자,
Canvas 객체는 액자에 넣어질 그림으로 비유될 수 있다.