How to use

add

method

in

org.jfree.data.xy.VectorSeries

/**
 * Adds a data item to the series.
 *
 * @param x  the x-value.
 * @param y  the y-value.
 * @param deltaX  the vector x.
 * @param deltaY  the vector y.
 */
public void add(double x, double y, double deltaX, double deltaY) {
  add(new VectorDataItem(x, y, deltaX, deltaY), true);
}
 

ser.add(((Number)valx).doubleValue(), ((Number)valy).doubleValue(), 0, 0);