Question

I’m learning Java and I have no idea how to do this.

I dragged a button on the form in Netbeans, double clicked it and it created this event:

@Action
public void HelloClickMethod() 
{
    JOptionPane.showMessageDialog(this, "The message!", "This is supposed to be the MessageBox title."); 
}

This is the exception the IDE brings up.

Cannot find symbol. Symbol: showMessageDialog()

Edit 1>
Now I changed it to this:

@Action
public void HelloClickMethod()
{
    JOptionPane.showMessageDialog(this, "The message!", "This is supposed to be the MessageBox title.",JOptionPane.ERROR_MESSAGE);
}

However the IDE is saying I have an error in the word ‘this’. “Cannot find symbol”. I don’t understand. Why is it so dificult and why are the errors so esoteric. 😛

Answer 1

I can think of the following cause: you might not be “importing” the package containing JOptionPane. Try:

 import javax.swing.*;

On top of your source file. Or, use

javax.swing.JOptionPane.showMessageDialog(this, "The message!", "This is supposed to be the MessageBox title.", JOptionPane.ERROR_MESSAGE);

After questioner edit:

Other cause is the location of the method, if you are in an static context, you can’t use this.