Looks to me like you are still not doing what the parent poster
suggested. Where did you put the

g2.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING,
                    RenderingHints.VALUE_TEXT_ANTIALIAS_OFF);

??

And are you sure you are meant to dispose of the Graphics when you are
finished?

I would expect that:

class JTextAreaAA extends JTextArea {
 public void paintComponent(Graphics g) {
    Graphics2D g2 = (Graphics2D) g.create() ;       
    g2.setRenderingHint(
        RenderingHints.KEY_RENDERING,
        RenderingHints.VALUE_RENDER_SPEED
    ) ;
    g2.setRenderingHint(
        RenderingHints.KEY_TEXT_ANTIALIASING,
        RenderingHints.VALUE_TEXT_ANTIALIAS_ON
    ) ;
    super.paintComponent(g2) ;
    g2.setRenderingHint(
        RenderingHints.KEY_TEXT_ANTIALIASING,
        RenderingHints.VALUE_TEXT_ANTIALIAS_OFF
    ) ;
 }
}

would do what you need.

I would intuitively expect that disposing the Graphics object would mean
that the UI would have to recreate it each time for the rest of the UI
to use . . . ?

From the JavaDocs for Graphics:

public abstract void dispose()

    Disposes of this graphics context and releases any system resources
that it is using. A Graphics object cannot be used after dispose has
been called.

[snip]

    Graphics objects which are provided as arguments to the paint and
update methods of components are automatically released by the system
when those methods return. *For efficiency, programmers should call
dispose when finished using a Graphics object only if it was created
directly from a component or another Graphics object.*

Check the sentence between *'s.

Rogan