Awkward API:

    yAxis.setTickLabelFormatter(new NumberAxis.DefaultFormatter(yAxis, null, null));

where we reference yAxis twice.


We could have either

    yAxis.setTickLabelFormatter(new NumberAxis.DefaultFormatter(null, null));

or if the formatter must have access to the axis then either:

    we add new API: NumberAxis.setAxis(yAxis) (and internally yAxis.setTickLabelFormatter calls that)

or just:

    new NumberAxis.DefaultFormatter(yAxis, null, null); (and internally it could do: yAxis.setTickLabelFormatter()); in its constructor)