code: public Database get_db_obj(final String host, final String port) throws DevFailed {
          if (ApiUtil.getOrb() == null) {
              create_orb();
          }
  
          // If first time, create vector
          if (db_list == null) {
              db_list = new ArrayList<Database>();
          }
  
          // Build tango_host string
          final String tango_host = host + ":" + port;
  
          // Search if database object already created for this host and port
          if (defaultDatabase != null) {
              if (defaultDatabase.get_tango_host().equals(tango_host)) {
                  return defaultDatabase;
              }
          }
  
          for (final Database dbase : db_list) {
              if (dbase.get_tango_host().equals(tango_host)) {
                  return dbase;
              }
          }
  
          // Else, create a new database object
          final Database dbase = new Database(host, port);
          db_list.add(dbase);
          return dbase;
      }
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