Java Applet question

From:

yingjian.ma1955@gmail.com

Newsgroups:

comp.lang.java.programmer

Date:

24 Apr 2006 17:06:59 -0700

Message-ID:

<1145923619.832981.144280@t31g2000cwb.googlegroups.com>

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

TestColor.java 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 = Color.blue;
    else if (s1.equals("red"))
        c = Color.red;
    else if (s1.equals("green"))
        c = Color.green;
    else
        c = Color.cyan;
    setBackground(c); }}

Html code:

<HTML>
<HEAD>
<TITLE>A Simple Program</TITLE>
</HEAD>
<BODY>
<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.
</APPLET>
</BODY>
</HTML>

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:

java.lang.NullPointerException
    at TestColor.init(TestColor.java:9)
    at sun.applet.AppletPanel.run(AppletPanel.java:378)
    at java.lang.Thread.run(Thread.java:595)
Warning: classic VM not supported; client VM will be used.

What is the bug?

Thanks a lot.