The following shows a Java example that returns a LineString object.
public static LineString buildLineString() throws Exception
{
LineString lineString = new LineString();
lineString.setSrsName("EPSG:4326");
//add the first point.
Pos pos = new Pos();
pos.setX(-75.44);
pos.setY(45.66);
pos.setMValue(new Double(54.33));
lineString.getPos().add(pos);
Pos pos1 = new Pos();
pos1.setX(-73.44);
pos1.setY(43.66);
pos1.setMValue(new Double(54.33));
lineString.getPos().add(pos1);
Pos pos2 = new Pos();
pos2.setX(-74.44);
pos2.setY(45.66);
pos2.setMValue(new Double(54.33));
lineString.getPos().add(pos2);
return lineString;
}