code: public static Geometry clip(Geometry geometry, Envelope envelope,
  			SpatialReference spatialReference) {
  		OperatorClip op = (OperatorClip) factory
  				.getOperator(Operator.Type.Clip);
  		Geometry result = op.execute(geometry, Envelope2D.construct(
  				envelope.getXMin(), envelope.getYMin(), envelope.getXMax(),
  				envelope.getYMax()), spatialReference, null);
  		return result;
  	}
docs: Calculates the clipped geometry from a target geometry using an envelope.
  
  See OperatorClip.
  
  @param geometry
  The geometry to be clipped.
  @param envelope
  The envelope used to clip.
  @param spatialReference
  The spatial reference of the geometries.
  @return The geometry created by clipping.