code: public synchronized void flush(boolean b) {
          if (com.ibm.websphere.ras.TraceComponent.isAnyTracingEnabled() && LoggingUtil.SESSION_LOGGER_WAS.isLoggable(Level.FINE)) {
              LoggingUtil.SESSION_LOGGER_WAS.entering(methodClassName, methodNames[FLUSH], "(" + b + ") session = " + this);
          }
          cacheLastAccessedTime = b;
          //we're going to call _sessions.put instead of storeSession to handle the case when it hasn't been inserted yet into the backend
          //if it hasn't been inserted we need to call insertSession, otherwise we just call storeSession.
          //_sessions.storeSession(this);
          _sessions.put(this.getId(), this);
          if (com.ibm.websphere.ras.TraceComponent.isAnyTracingEnabled() && LoggingUtil.SESSION_LOGGER_WAS.isLoggable(Level.FINE)) {
              LoggingUtil.SESSION_LOGGER_WAS.exiting(methodClassName, methodNames[FLUSH]);
          }
      }
docs: /*
  Method flush(boolean)
  
  @see com.ibm.wsspi.session.ISession#flush(boolean)