阅读下面的程序,在空格处填上相应的代码import java.awt.*;;public class JFrameExample1 {public static void main(String args[]) {JFrameExample1 obj = new JFrameExample1();obj.myJFrame();}public void myJFrame() {JFrame jframe = new JFrame("一个框架应用");Container panel = jframe.getContentPane();panel.setLayout(new FlowLayout());panel.add(new JButton(" 欢迎使用!"));jframe.setSize(300, 150);jframe.show();}}