Class can't be instantiated.

[3maksim]

Hello,
Im new into java and especially in applets.
I have two classes Say.java and SayWhat.java.
Say.java contains following code:

public class Say {
	SayWhat word = new SayWhat("hello");
}

and SayWhat.java contains:

import java.applet.Applet;
import java.awt.Graphics;

@SuppressWarnings("serial")
public class SayWhat extends Applet {
	 Graphics g;
	public SayWhat(String what) {
		paint(what,g);
	}
	public void paint(String string, Graphics g){
		g.drawString(string, 20, 20);
	}
}

When im trying to compile it, it throws me an error:

load: SayWhat.class can't be instantiated.
java.lang.InstantiationException: SayWha
at java.lang.Class.newInstance0(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at sun.applet.AppletPanel.createApplet(Unknown Source)
at sun.applet.AppletPanel.runLoader(Unknown Source)
at sun.applet.AppletPanel.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

Can please someone explain me what am I doing wrong?

[Norm]

That error message looks like an execution error not a compile error.
What command are you executing when you get that error?

Where is the ending t on this: java.lang.InstantiationException: SayWha

[pbrockway2]

When im trying to compile it, it throws me an error:

load: SayWhat.class can't be instantiated.
java.lang.InstantiationException: SayWha
at java.lang.Class.newInstance0(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at sun.applet.AppletPanel.createApplet(Unknown Source)
at sun.applet.AppletPanel.runLoader(Unknown Source)
at sun.applet.AppletPanel.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

That's not a compiler message, it's a runtime error message and it's occuring when your applet attempts to run (as part of a web page etc).

According to the first line of the error message you are attempting to use a class SayWha. It looks like you have made a typo and forgotten the last letter of the class. This is probably in the web page or wherever you specified the class to run.

[3maksim]

Typo is fixed now and actually im trying to run it in Eclipse at the moment. Problem still occurs and I cant figure it out why it is not working.

[Norm]

Please post the full text of the error message.

[3maksim]

Full text of error message is in the first post, there is no more info.

load: SayWhat.class can't be instantiated.
java.lang.InstantiationException: SayWhat
at java.lang.Class.newInstance0(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at sun.applet.AppletPanel.createApplet(Unknown Source)
at sun.applet.AppletPanel.runLoader(Unknown Source)
at sun.applet.AppletPanel.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

[Norm]

Why does the SayWhat class extend Applet? Having the class extend Applet makes no sense for the way you are using it.
For a test, remove the extends part of the class definition and see what happens.

[3maksim]

hmm.
You extend an Applet to have an Applet.
Seems like im in a wrong place.

[Norm]

If you want to execute an applet you use an applet tag in an HTML file to start its execution.
Your Say class (an application) is trying to create an instance of the SayWhat class.

Do you know how to write and execute applets?
See:Lesson: Java Applets (The Java™ Tutorials > Deployment)

[3maksim]

Im executing the code in Eclipse.

[Norm]

Sorry, I have no idea how your IDE works or how to use it.
If you need help with your IDE, there is a section of the forum for IDEs.

[pbrockway2]

You can run applets in Eclipse using the "Run as..." command and selecting "Applet".

Your applet will not be able to be instantiated because it does not have a no argument constructor. It is not usual to define *any* constructor for an applet - and, in that case it will use the default no argument constructor.

Have a look at Java Applets lesson in Oracle's Tutorial and especially the sections on the so called "milestone" methods to see what methods you have to write for an applet and how you would use them to provide the applet with specific behaviour (like printing a specific word). Note that this lesson uses JApplet.

[DarrylBurke]

Also, for an Applet or any other visual component, that painting code and instance Graphics variable are utterly wrong. find the section of the tutorial titled 'Performing Custom Painting' and learn from there.

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