Simple code, but wrong, please help.

Question

I wrote the follow code. When I call it in another class but no disaply. What happens? Please help me to correct it. Thanks.
import java.awt.*;
import java.awt.geom.*;
import javax.swing.*;
public class tempStr extends JApplet{
final static Color bg = Color.white;
final static Color fg = Color.black;
String str;
tempStr(String string){
     str=string;
     JFrame f = new JFrame("string draw");
        JApplet applet1 = new tempStr(str);
        f.getContentPane().add("Center", applet1);
        applet1.init();
        f.pack();
       f.setSize(new Dimension(400,400));
        f.show();
    public void init() {
        setBackground(bg);
        setForeground(fg);
public void paint(Graphics g) {
  Graphics2D g2=(Graphics2D)g;
    g2.drawString(str, 40,160);
  }

Answer 1

It would be better to move the creation code into some dedicated method:
import java.awt.*;
import java.awt.geom.*;
import javax.swing.*;
public class tempStr extends JApplet{
    final static Color bg = Color.white;
    final static Color fg = Color.black;
    String str;
    tempStr(String string){
        str=string;
    public void init() {
        setBackground(bg);
        setForeground(fg);
    public void paint(Graphics g) {
        Graphics2D g2=(Graphics2D)g;
        g2.drawString(str, 40,160);
    public static void main(String argv[]) {
        JFrame f = new JFrame("string draw");
        JApplet applet1 = new tempStr(argv[0]);
        f.getContentPane().add("Center", applet1);
        applet1.init();
        f.pack();
        f.setSize(new Dimension(400,400));
        f.show();
}To lauch the applet from command line:
java tempStr "Hello world"