code: protected synchronized void initialize() {
          if (initialized)
              return;
          scrSessionContexts = new Hashtable();
          scrInstance = this; // see com.ibm.ws.session.SessionData#invalidateAll(boolean)
          SessionManagerConfig smc = getServerSMC();
  
          _globalSessionContext = SessionManagerConfig.getServlet21SessionCompatibility();
          if (_globalSessionContext) {
              LoggingUtil.SESSION_LOGGER_CORE.logp(Level.INFO, methodClassName, methodNames[INITIALIZE], "SessionContextRegistry.globalSessionsEnabled");
  
              if (LoggingUtil.SESSION_LOGGER_CORE.isLoggable(Level.WARNING)) {
                  if (smc.getEnableTimeBasedWrite()) {
                      LoggingUtil.SESSION_LOGGER_CORE.logp(Level.WARNING, methodClassName, methodNames[INITIALIZE], "SessionContextRegistry.globalSessionTBWWarning");
                  }
                  if (smc.isUsingMemtoMem()) {
                      LoggingUtil.SESSION_LOGGER_CORE.logp(Level.WARNING, methodClassName, methodNames[INITIALIZE], "SessionContextRegistry.globalSessionM2MWarning");
                  }
              }
          }
  
          initialized = true;
      }
docs: /*
  initialize