code: public SimpleFeature convertDwgArc( String typeName, String layerName, DwgArc arc, int id ) {
          double[] c = arc.getCenter();
          Point2D center = new Point2D.Double(c[0], c[1]);
          double radius = (arc).getRadius();
          double initAngle = Math.toDegrees((arc).getInitAngle());
          double endAngle = Math.toDegrees((arc).getEndAngle());
          Point2D[] ptos = GisModelCurveCalculator.calculateGisModelArc(center, radius, initAngle,
                  endAngle);
          CoordinateList coordList = new CoordinateList();
          for( int j = 0; j < ptos.length; j++ ) {
              Coordinate coord = new Coordinate(ptos[j].getX(), ptos[j].getY(), 0.0);
              coordList.add(coord);
          }
  
          SimpleFeatureTypeBuilder b = new SimpleFeatureTypeBuilder();
          b.setName(typeName);
          b.setCRS(crs);
          b.add(THE_GEOM, LineString.class);
          b.add(LAYER, String.class);
          SimpleFeatureType type = b.buildFeatureType();
          SimpleFeatureBuilder builder = new SimpleFeatureBuilder(type);
          Geometry lineString = gF.createLineString(coordList.toCoordinateArray());
          Object[] values = new Object[]{lineString, layerName};
          builder.addAll(values);
          return builder.buildFeature(typeName + "." + id);
      }
docs: Builds a line feature from a dwg arc.