The specs for java.awt.RadialGradientPaint says:
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"Specifying a focus point outside of the circle's radius will result in the focus being set to the intersection point of the focus-center line and the perimeter of the circle."
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However the following sample shows it does not happen in case of RI.
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        float cx = 0.0f;
        float cy = 0.0f;
        float radius = 10.0f;
        float fx = 20.f;
        float fy = 0.0f;

        Point2D expectedFocus = new Point2D.Float(10.0f, 0.0f);

        RadialGradientPaint gp = new RadialGradientPaint(cx, cy, radius, fx, fy,
                new float[] { 0.0f, 0.5f, 1.0f},
                new Color[] { Color.RED, Color.GREEN, Color.BLUE },
                CycleMethod.NO_CYCLE);
        Point2D actualFocus = gp.getFocusPoint();

        if ( ! expectedFocus.equals(actualFocus)) {
            System.out.println("FAIL. Expected focus point: " + expectedFocus
                    + "\nActual focus point: " + actualFocus);
        }
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The output produced:
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FAIL. Expected focus point: Point2D.Float[10.0, 0.0]
Actual focus point: Point2D.Double[20.0, 0.0]
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The sample source attached.