GUI manipulation outside EDT in AWT not SWING

Question

The question is whether java.awt.Canvas.setBackground(Color) may safely be called from the main thread (i.e. outside event dispatch thread) without risk of crashing.

Background

I am drafting an undergraduate lession about finite automata and seek a way to visualise their behaviour. I do not want to distract my students' attention from the subject by threading issues. Java Swing requires precautions concerning threads when setting up and changing the GUI, see:

• How to use Thread.sleep() and setBackground() to create flash effect in Swing?
• About the EDT (Java)

So Swing appears not to be an option at this stage. The above articles seem to be concerned about Swing rather than AWT. As to AWT, I read in

• must all methods in AWT classes, i.e. non-Swing ones, be called in the EDT?

the promising statement that

AWT Components were intended to be thread safe

Question re-worded

Is sufficient thread-safety documented in the AWT documentation so that I can rely on it for the Canvas class in all JREs?

Demo code sample

The AWT-related code I am talking about is as simple as the following colour-changer in Colours.java:

 import java.awt.Frame;
 import java.awt.Canvas;
 import java.awt.Color;

 /** Demonstrates Java AWT operated from main thread. */
 public class Colours {
    private static final Color[] colours = {
       Color.RED, Color.GREEN, Color.BLUE
    };
    public static void main ( final String[] arguments ) {
       final Frame frame = new Frame( "Colours" );
       final Canvas canvas = new Canvas();
       frame.setSize( 320, 200 );
       frame.add( canvas );
       frame.setVisible( true );
       final ExitListener exitListener = new ExitListener();
       frame.addWindowListener( exitListener );
       int choice = 0;
       while ( ! exitListener.isExiting() ) {
          canvas.setBackground( colours[choice] );
          if ( ++choice >= colours.length ) {
             choice = 0;
          }
          try {
             Thread.sleep( 1000 );
          } catch ( final InterruptedException e ) {}
       }
    }
 }

and ExitListener.java:

 import java.awt.Window;
 import java.awt.event.WindowEvent;
 import java.awt.event.WindowListener;

 public class ExitListener implements WindowListener {

    private boolean isExiting = false;

    public boolean isExiting () {
       return isExiting;
    }

    @Override
    public void windowActivated ( final WindowEvent e ) {}

    @Override
    public void windowClosed ( final WindowEvent e ) {}

    @Override
    public void windowClosing ( final WindowEvent e ) {
       isExiting = true;
       final Window window = e.getWindow();
       window.dispose();
    }

    @Override
    public void windowDeactivated ( final WindowEvent e ) {}

    @Override
    public void windowDeiconified ( final WindowEvent e ) {}

    @Override
    public void windowIconified ( final WindowEvent e ) {}

    @Override
    public void windowOpened ( final WindowEvent e ) {}
 }

N.B.: java.awt.event.WindowAdapter has not been used on purpose, because inheritance of state will be covered later in the course.