Method javax.swing.plaf.nimbus.AbstractRegionPainter.decodeRadialGradient(...) throws unspecified IllegalArgumentException for negative radius values. It should be specified.

Please see the following code sample:
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import javax.swing.*;
import java.awt.*;
import static java.awt.Color.*;
public class Test {
    public static void main(String[] args) {
        class MyARP extends javax.swing.plaf.nimbus.AbstractRegionPainter {
            protected PaintContext getPaintContext() { return null; }
            protected void doPaint(Graphics2D g, JComponent c,
                                   int width, int height,
                                   Object[] extendedCacheKeys) { }
            void callWithNegRadius() {
                float radius = -1.f;
                decodeRadialGradient(0.1f, 0.5f, radius,
                        new float[]{.1f, 0.2f}, new Color[]{BLACK, BLUE});
            }
        }
        new MyARP().callWithNegRadius();
    }
}
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Execution will lead to:

Exception in thread "main" java.lang.IllegalArgumentException: Radius must be greater than zero
at java.awt.RadialGradientPaint.<init>(RadialGradientPaint.java:451)
at java.awt.RadialGradientPaint.<init>(RadialGradientPaint.java:387)
at java.awt.RadialGradientPaint.<init>(RadialGradientPaint.java:344)
at java.awt.RadialGradientPaint.<init>(RadialGradientPaint.java:176)
at javax.swing.plaf.nimbus.AbstractRegionPainter.decodeRadialGradient(AbstractRegionPainter.java:393)
at Test$1MyARP.callWithNegRadius(Test.java:15)
at Test.main(Test.java:19)