Administration guide > Troubleshoot

Troubleshoot client connectivity

There are several common problems specific to clients and client connectivity that you can solve as described in the following sections.


Problem: If you are using the EntityManager API or byte array maps with the COPY_TO_BYTES copy mode, client data access methods result in various serialization-related exceptions or a NullPointerException exception.

Cause: The EntityManager API and COPY_TO_BYTES copy mode use a metadata repository that is embedded in the data grid. When clients connect, the data grid stores the repository identifiers in the client and caches the identifiers for the duration of the client connection. If you restart the data grid, you lose all metadata and the regenerated identifiers do not match the cached identifiers on the client.

Solution: If you are using the EntityManager API or the COPY_TO_BYTES copy mode, disconnect and reconnect all of the clients if the ObjectGrid is stopped and restarted. Disconnecting and reconnecting the clients refreshes the metadata identifier cache. You can disconnect clients by using the ObjectGridManager.disconnect method or the ObjectGrid.destroy method.

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