i need to find if the node is in offline or online
The atom object is what you are looking for, however, as a best practices you should look at multiple facets of determining an Atom status.
JMX Monitoring - System monitoringwith JMX
If you are using Web API - you should use a heartbeat check so an API URL.
You should also monitor your local host process, if windows or *nix you will need to find the best solution for your platform and third party monitoring licensing model.
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