Display error message for JSlider

Hi, I have create a Java app using BlueJ, in which you can change the size of a selected shape using a JSlider. One of the shapes to choose from is just a 'point', the size of a pixel, whose size i do not want to be changed.

I am trying to get an error message to display when the 'point' shape is selected and the user tries to change the size using the JSlider. The code I have got is shown below. The problem I have is that the error message is displayed loads of times in the terminal window if you drag the slider a large amount, it is displayed for each time the slider changes by 1, if that makes sense. Is there any way I can get the error message to display just once no matter how far the slider has moved?

"
//When the slider is moved the following method will be called
public void stateChanged(ChangeEvent e) {

//Rewrite the label reflecting the new value of the slider
label.setText("Size: " + adjustsize.getValue() + " pixels");

//Change size of shape when slider is moved
adjustsize = (JSlider)e.getSource();

newSize = adjustsize.getValue();
aShape.reSize(newSize);

//If Point shape is selected display error message
if (aShape == firstPoint) {

System.out.println("You can't resize a point");

//Repaint the window to reflect the updates made
repaint();
}

"

Thanks!