下面的例子，第一个正确，为什么第二个错误那？

第一个：
import java.awt.*;
import javax.swing.*;
public class Text extends JFrame{
public Text(){
Container con = getContentPane();
con.setLayout(new FlowLayout(FlowLayout.LEFT));
JPanel p1 = new JPanel();
JPanel p2 = new JPanel();
for(int i=1;i<=6;i++){
if(i<=3) p1.add(new JButton("The "+i));
else p2.add(new JButton("The "+i));
}
con.add(p1);
con.add(p2);
}
public static void main(String[] args){
Text text = new Text();
text.setTitle("My Frame");
text.setSize(250,150);
text.setVisible(true);
text.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}
第二个：
import java.awt.*;
import javax.swing.*;
public class Text extends JFrame{
public Text(){
Container con = getContentPane();
con.setLayout(new FlowLayout(FlowLayout.LEFT));