How to use

GetAuthorityCode

method

in

org.gdal.osr.SpatialReference

@Override
public String SpatialRefGetAuthorityCode(Object spatialRef, String authority) {
  return ((SpatialReference) spatialRef).GetAuthorityCode(authority);
}

String code = sref.GetAuthorityCode(null);
if (code != null) {
  crs = Proj.crs("epsg:" + code);