docs: public static String getHadoopUser() {
  		try {
  			Class<?> ugiClass = Class.forName(
  				"org.apache.hadoop.security.UserGroupInformation",
  				false,
  				EnvironmentInformation.class.getClassLoader());
  
  			Method currentUserMethod = ugiClass.getMethod("getCurrentUser");
  			Method shortUserNameMethod = ugiClass.getMethod("getShortUserName");
  			Object ugi = currentUserMethod.invoke(null);
  			return (String) shortUserNameMethod.invoke(ugi);
  		}
  		catch (ClassNotFoundException e) {
  			return "<no hadoop dependency found>";
  		}
  		catch (LinkageError e) {
  			// hadoop classes are not in the classpath
  			LOG.debug("Cannot determine user/group information using Hadoop utils. " +
  					"Hadoop classes not loaded or compatible", e);
  		}
  		catch (Throwable t) {
  			// some other error occurred that we should log and make known
  			LOG.warn("Error while accessing user/group information via Hadoop utils.", t);
  		}
  		
  		return UNKNOWN;
  	}