### Question:
PenStroke extends Stroke implements FillNode { public void setLineJoin(LineJoin join) { lineJoin = join == null ? DEFAULT_JOIN : join; } PenStroke();  PenStroke(PenStrokeType t);  PenStroke(JAXBElement<PenStrokeType> s); @Override Double getNaturalLength(Map<String,Object> map, Shape shp, MapTransform mt); @Override Double getNaturalLengthForCompound(Map<String,Object> map,
            Shape shp, MapTransform mt); @Override List<SymbolizerNode> getChildren(); @Override Fill getFill(); @Override void setFill(Fill fill); void setLineCap(LineCap cap); LineCap getLineCap(); void setLineJoin(LineJoin join); LineJoin getLineJoin(); void setWidth(RealParameter width); RealParameter getWidth(); RealParameter getDashOffset(); void setDashOffset(RealParameter dashOffset); StringParameter getDashArray(); void setDashArray(StringParameter dashArray); BasicStroke getBasicStroke(Map<String,Object> map, MapTransform mt, Double v100p); @Override void draw(Graphics2D g2, Map<String,Object> map, Shape shape,
            boolean selected, MapTransform mt, double offset); double getWidthInPixel(Map<String,Object> map, MapTransform mt); double getMinLength(Map<String,Object> map, MapTransform mt); @Override JAXBElement<PenStrokeType> getJAXBElement(); PenStrokeType getJAXBType(); static final double DEFAULT_WIDTH; static final LineCap DEFAULT_CAP; static final LineJoin DEFAULT_JOIN; }### Answer:
@Test public void testSetLineJoin() throws Exception { PenStroke ps = new PenStroke(); assertEquals(ps.getLineJoin(), PenStroke.LineJoin.MITRE); ps.setLineJoin(null); assertEquals(ps.getLineJoin(), PenStroke.LineJoin.MITRE); ps.setLineJoin(PenStroke.LineJoin.BEVEL); assertEquals(ps.getLineJoin(), PenStroke.LineJoin.BEVEL); }