How to make Applet in NetBeans?

Newbie & Debugging Questions
#1

I need to create applet for Java4kb competition. Basicly, what should I click in NetBeans IDE to make one of these templates “compile” (I’m getting “can’t find main()”)?

And yes, I was unable to google it, which is kind of strange since something that basic should be covered somewhere…

#2

Applets don’t have main methods. Netbeans should automatically run your applet in the AppletViewer when you hit the run button. What problems did you encounter?

#3

NetBeans 7.1

Let’s say I want to run this simple HelloWorld code from wikipedia:


import java.applet.Applet;
import java.awt.*;
 
// Applet code for the "Hello, world!" example.
// This should be saved in a file named as "HelloWorld.java".
public class HelloWorld extends Applet {
  // This method is mandatory, but can be empty (i.e., have no actual code).
  public void init() { }
 
  // This method is mandatory, but can be empty.(i.e.,have no actual code).
  public void stop() { }
 
  // Print a message on the screen (x=20, y=10).
  public void paint(Graphics g) {
    g.drawString("Hello, world!", 20,10);
 
  // Draws a circle on the screen (x=40, y=30).
    g.drawArc(40,30,20,20,0,360);
  }
}

I click:

  • NewProject/Java/JavaApplication
  • Set project name to: “AppletHelloWorld”, Finish
  • click on AppletHelloWorld.java, I see this:

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package applethelloworld;

/**
 *
 * @author Admin
 */
public class AppletHelloWorld {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
	// TODO code application logic here
    }
}
  • I copy/past the code and change “public class HelloWorld extends Applet” to “public class AppletHelloWorld extends Applet”
import java.applet.Applet;
import java.awt.*;
 
// Applet code for the "Hello, world!" example.
// This should be saved in a file named as "HelloWorld.java".
public class AppletHelloWorld extends Applet {
  // This method is mandatory, but can be empty (i.e., have no actual code).
  public void init() { }
 
  // This method is mandatory, but can be empty.(i.e.,have no actual code).
  public void stop() { }
 
  // Print a message on the screen (x=20, y=10).
  public void paint(Graphics g) {
    g.drawString("Hello, world!", 20,10);
 
  // Draws a circle on the screen (x=40, y=30).
    g.drawArc(40,30,20,20,0,360);
  }
}
  • click Run, “BUILD SUCCESSFUL (total time: 0 seconds)”, nothing appears on the screen
  • Click “Clean and Build Main Project”, click Run again, get an error “applethelloworld.AppletHelloWorld class wasn’t found in AppletHelloWorld project; select the main class”.

I guess, I clicked something wrong along the way :slight_smile:
I was checking several tutorials but I always stumbled on some differences (like there is no “Run as Applet” option in NetBeans 7.1 or the option they select in the tutorial does not exist)

#4

you can go to the project properties
Application->Web Start
-Enable Web Start
-Applet descriptor

I do it a bit different I create a Component like a Canvas which I can attach to an applet or jframe, depending on how I build it(desktop or applet)

#5

No change, still “class not found”. Also I’m getting now an icon “AppletHelloWorld needs to be compiled”, no matter what I click I can’t make it disappear.

#6

I just opened up Netbeans, wrote a little test applet, and wow I’m getting the same error: “Main class not found.”

Another reason why Eclipse > Netbeans (please let’s not start an IDE war…) ;D

#7

In Eclipse it works like a charm… And I was already so used to the faster launch speed of NetBeans :frowning:

#8

you just have to hit SHIFT+F6(run file) while being in your applet class file in netbeans

#9

Google Chrome’s Java installation messes up netbeans applets.

#10

google chromes java? - what could you possible do with an applet so that it have browser specific behavior
netbeans applets? - why do you think so? what settings
messes up? - what happens?

#11

I made a simple hello world applet in netbeans, didnt work, uninstalled google chrome’s java, recompiled and ran, worked perfectly.

#12

There is no such thing as “Google Chrome’s Java”. There is only 1 Java installation.

#13

Chrome has its own java installation for their browser.

#14

You mean that “chromeinstall.exe” file that you click? All that does is download the JRE for system-wide use…

#15

It still breaks applets when you use netbeans

#16

Well I blame Netbeans :slight_smile: