code: @Override
  	public boolean isConnected() {
  		try {
  			ResultSet rs = executeSelectSQL("SELECT 1", null);
  			if (rs.next()) {
  				return true;
  			}
  			return false;
  		} catch (DatabaseException e) {
  			e.printStackTrace();
  			return false;
  		} catch (SQLException e) {
  			e.printStackTrace();
  			return false;
  		}
  
  	}
docs: based on simple query
  http://stackoverflow.com/questions/5276816/how-to-determine
  -if-java-sql-connection-is-valid-with-postgresql-jdbc4