Error Codes and Safe Responses

MiddlewareException carries a transport-neutral RemoteError and stable MiddlewareErrorCode. Inspect the code and the operation's entry/identity contract. Do not decide retry safety from arbitrary message text.

Code	Meaning and response
NOT_FOUND	The requested service/object/record is absent; verify identity, context and lifecycle
UNAVAILABLE	A target/subsystem cannot currently provide the operation; inspect the failed boundary
DEADLINE_EXCEEDED	The operation exceeded its budget; entered effects may still need reconciliation
CANCELLED	Cancellation was observed; physical exit/undo is not implied
OVERLOADED	A finite capacity limit rejected work; apply backpressure rather than unbounded retry
PERMISSION_DENIED	Authenticated caller lacks authority; fix policy/identity through the proper owner
UNAUTHENTICATED	Caller identity was not established; repair credentials/transport admission
INVALID_ARGUMENT	Invalid options, metadata or request shape; correct input before retrying
METHOD_NOT_FOUND	The target does not expose that method
INTERFACE_MISMATCH	The expected Java contract is absent or incompatible
CODEC_ERROR	Encoding/decoding failed; inspect allowed types, schema and size
REMOTE_EXCEPTION	Entered application code threw; do not infer safe replay
LEASE_EXPIRED	The reference/record lease expired; obtain valid current state
DUPLICATE_OPERATION	The reliability contract rejected a duplicate/conflicting operation
STALE_FENCING_TOKEN	Presented ownership is obsolete; stop using that authority
REGISTRY_UNAVAILABLE	Discovery/registry could not satisfy the request
TRANSPORT_ERROR	Failure before or during transport; entry status determines retry safety
LOG_CORRUPTION	Durable record/segment integrity failed; preserve evidence and follow recovery policy
DURABLE_LOG_ERROR	Durable I/O/sync/format operation failed
RECOVERY_FAILED	Recovery could not complete safely, including explicit bounded-work failures
INTERNAL	Unexpected middleware failure; retain safe diagnostics and investigate

Native resource replies also have domain-specific states, such as stale generation/receipt or UNKNOWN. They are not additional members of this enum. Preserve the typed/resource-specific outcome rather than converting every non-success into a new request.

Network bootstrap deliberately exposes the fixed safe Bootstrap endpoint unavailable error for connection/protocol failures. Its diagnostics must not leak certificate secrets, raw payloads or arbitrary exception messages. Check reachability, trust, context and bounds using safe host observations.

Source: MiddlewareErrorCode (repository source: j7m-api/src/main/java/org/j7m/middleware/api/MiddlewareErrorCode.java).