code: public Enumeration tableKeys() {
          if (com.ibm.ejs.ras.TraceComponent.isAnyTracingEnabled() && LoggingUtil.SESSION_LOGGER_CORE.isLoggable(Level.FINE)) {
              LoggingUtil.SESSION_LOGGER_CORE.logp(Level.FINE, methodClassName, "tableKeys", appNameForLogging);
          }
          Set keys = (_sessions != null) ? _sessions.keySet() : (new HashMap(1)).keySet();
  
          final Iterator iter = keys.iterator();
          return new Enumeration() {
  
              @Override
              public boolean hasMoreElements() {
                  return iter.hasNext();
              }
  
              @Override
              public Object nextElement() {
                  return iter.next();
              }
          };
      }
docs: /*
  tableKeys()
  returns id's of all sessions