@Override
  public boolean isConnected() {
    boolean result = false;
    synchronized (CONN_SYNC) {
      result = ((system != null) && system.isConnected());
    }
    return result;
  }
Returns true if this Agent is currently connected to a system.
geode-core/src/main/java/org/apache/geode/admin/jmx/internal/AgentImpl.java