code: private static boolean polylineEqualsEnvelope_(Polyline polyline_a,
  			Envelope envelope_b, double tolerance,
  			ProgressTracker progress_tracker) {
  		Envelope2D env_a = new Envelope2D(), env_b = new Envelope2D();
  		polyline_a.queryEnvelope2D(env_a);
  		envelope_b.queryEnvelope2D(env_b);
  
  		if (env_b.getHeight() > tolerance && env_b.getWidth() > tolerance)
  			return false; // area cannot equal a line
  
  		return envelopeEqualsEnvelope_(env_a, env_b, tolerance,
  				progress_tracker);
  	}
docs: Returns true if polyline_a equals envelope_b.