code: public Envelope lngLatToMeters(Envelope env) {
          Coordinate min = lngLatToMeters(env.getMinX(), env.getMinY());
          Coordinate max = lngLatToMeters(env.getMaxX(), env.getMaxY());
          Envelope result = new Envelope(min.x, max.x, min.y, max.y);
          return result;
      }
docs: Transforms given lat/lon in WGS84 Datum to XY in Spherical Mercator
  EPSG:3857
  
  @param env The envelope to transform
  @return The envelope transformed to EPSG:3857