Applet leaves cmd prompt hanging afr exit under 1.3.1_02, ok under 1.2.2

Question

Subject: Applet leaves cmd prompt hanging afr exit under 1.3.1_02, ok under 1.2.2
I am working with examples from a Java book. My applets leaving the command promt hanging after closing them by clicking the X in the upper left corner. I am running Windows NT 4.0, svc pack 6.
After the applet is ended the command window hangs and won't respond to ctrl-c. If I attempt to close the command window a message box appears saying the command window is unable to respond to the end request (busy or waiting) and gives me the option to wait / end / cancel.
This has happened with all the applet examples I have tried and some Sun JAI examples.
Here is an example from a Java primer:
import java.applet.Applet;
import java.awt.Graphics;
<applet code="AppletLifecycle" width=300 height=50>
</applet>
public class AppletLifecycle extends Applet {
String str = "";
public void init() {
str += "init; ";
public void start() {
str += "start; ";
public void stop() {
str += "stop; ";
public void destroy() {
System.out.println("destroy");
public void paint(Graphics g) {
g.drawString(str, 10, 25);
import java.applet.*;
import java.awt.*;
<applet code="FirstApplet" width=400 height=400>
</applet>
public class FirstApplet extends Applet {
public void paint(Graphics g) {
g.drawString("This is my first applet!", 20, 200);
After compling, from the command line I enter:
C:> appletviewer AppletLifecycle.java (or AppletLifecycle.htm)
The applet comes up correctly.
If I close the applet by clicking the X in the upper right corner
- the applet window goes blank
- "destroy" appears in the command window
- the command session is hung and will not respond to a ctrl-c to end the application
I either have to use task manager to kill the command session or click on the X in the upper right corner of the command window. Task manger says the command session is "not responding". Either way I get the message that the application cannot respond to the end task request (may be busy, waiting for a response, etc.) and the option to wait / end / cancel.
Under Java 1.2.2 after closing the applet the command session is "waiting" ("hung") until a ctrl-c is typed. Then the DOS promt returns and the command session is free.
This behavior is consistent with several of the applets in this text book.
I first encountered this problem when working with examples in the JAI (java advanced imaging) package from Sun. These samples run as applications and display an image. They work correctly but hang when I attempt to close them. I have tried the examples only under 1.3.1_02.
Can anyone help me figure this out?
Thanks
Bill

Answer 1

The book says that the destory method is is called when an applet is closed.
If the applet does not have a destroy method then the default destoy method
the the Applet class is called. Is that wrong or am I not understanding.The book and your understanding is correct. It's just that my experience has indicated that overriding the destroy method is not a good idea. The applet's stop method is called (by the appletviewer or a web browser) when it's ready to close or move onto another document, so any cleanup that you need to do should be done in the stop method. As far as browsers go, IE destroy the applet when you move to another document but Netscape 4+ only call the destroy method when the browser window is closed but there is no guarantee that NN4 will ever call the destroy method. That's the reason why I don't recommend overriding the destroy method -- but as long as you know what is in store for you, you can do anything you want.
BTW, I've compiled and tested the AppletLifecycle.java program on my JDK1.3.1 and it works with the appletviewer, IE5.5 and NN4.7. I have no trouble stoping the program from the MS-DOS window with a CTRL-C or click the little x on the upper right corner of the display. I do know that when I upgraded to 1.3.1_02, all my applets mysteriously stopped working so I went back to 1.3.1 -- maybe that's the reason why you're left hanging.
V.V.