Re: Java Applet question

"Amfur Kilnem" <>
Tue, 25 Apr 2006 01:20:45 GMT
<> wrote in message

I have a Java applet called TestColor that does not work. Here is the
code. code:

import java.awt.*;
import java.applet.*;
public class TestColor extends Applet {
String s1;
public void init() {
Color c;
s1 = getParameter("mycolor");
if (s1.equals("blue"))
c =;
else if (s1.equals("red"))
c =;
else if (s1.equals("green"))
c =;
c = Color.cyan;
setBackground(c); }}

Html code:

<TITLE>A Simple Program</TITLE>
<h2>Here is the applet:</h2><br>
<APPLET CODE="TestColor.class" WIDTH=550 HEIGHT=500 alt="white">
<param name="mycolor" value="blue">
Sorry, you aren't running a Java-capable browser.

If I change mycolor to adjective1 in both files. It works. Could you
kindly try it and tell me why?

When I run it in a debugger, I got this msg:

at TestColor.init(
Warning: classic VM not supported; client VM will be used.

What is the bug?

You are not checking the return value of getParameter(). If "mycolor" isn't
found, the returned value will be null, and the very next line will cause
the null pointer exception.

As to why it appears not to be working with "mycolor", maybe you have a
stale applet and/or HTML in your browser...?

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