code: public static Geometry difference(Geometry geometry1, Geometry substractor,
  			SpatialReference spatialReference) {
  		OperatorDifference op = (OperatorDifference) factory
  				.getOperator(Operator.Type.Difference);
  		Geometry result = op.execute(geometry1, substractor, spatialReference,
  				null);
  		return result;
  	}
docs: Creates the difference of two geometries. The dimension of geometry2 has
  to be equal to or greater than that of geometry1.
  
  See OperatorDifference.
  
  @param geometry1
  The geometry being subtracted.
  @param substractor
  The geometry object to subtract from.
  @param spatialReference
  The spatial reference of the geometries.
  @return The geometry of the differences.