1번 import javax.swing.*; public class Chapter9 extends JFrame { Chapter9(){ setDefaultCloseOperation(EXIT_ON_CLOSE); setTitle("Let's study Java"); setSize(400, 200); setVisible(true); } public static void main(String args[]){ new Chapter9(); } } 2번 import javax.swing.*; import java.awt.*; public class Chapter9 extends JFrame { Chapter9(){ setDefaultCloseOperation(EXIT_ON_CLOSE); setTitle("Border..