List lines = LinearComponentExtracter.getLines(g1);
// add second input's linework, if any
if (g2 != null)
LinearComponentExtracter.getLines(g2, lines);
List nodedLinework = new GeometryNoder(pm).node(lines);
// union the noded linework to remove duplicates
Geometry nodedDedupedLinework = geomFact.buildGeometry(nodedLinework).union();
// polygonize the result
Polygonizer polygonizer = new Polygonizer();