Kafka Streams: A Serializer Is Not Compatible to the Actual Type
Kafka Streams throws 'A serializer is not compatible to the actual key or value type' or 'ClassCastException invoking Processor'. Here's the SerDe fix.
kafka-errors
60 PostsKafka Streams RocksDBException: Too Many Open Files Fix
Kafka Streams dying with ProcessorStateException and RocksDBException 'Too many open files'? Here's the file-descriptor math and the config setter that fixes it.
Kafka Streams MissingSourceTopicException: Fix It Fast
Kafka Streams dies with MissingSourceTopicException on startup or rebalance. Here's why the assignor flags a missing source topic and how to fix it.
Kafka Streams LockException: Failed to Lock the State Directory
Kafka Streams throwing LockException: Failed to lock the state directory for task? Here's the exact cause, why it happens, and the fix.
Kafka Streams Deserialization Exception Handler: Fix the Fail
Kafka Streams dies with 'Deserialization exception handler is set to fail upon a deserialization error.' Here's why one bad record kills the thread and how to fix it.
Kafka SSL Handshake Failed: PKIX and Hostname Fixes
Fix org.apache.kafka.common.errors.SslAuthenticationException: SSL handshake failed — PKIX path errors, SAN mismatches, and listener protocol mixups fast.
Kafka SerializationException: Fixing Poison Pill Records
Kafka SerializationException: "Error deserializing key/value" crashes your consumer in a loop. Fix it with ErrorHandlingDeserializer and a dead letter topic.
Kafka SerializationException: Schema Not Found (40403) Fix
Kafka consumer dies with SerializationException: Error retrieving Avro schema for id N, Schema not found; error code: 40403. Why the ID lookup fails and how to fix it.
Schema Being Registered Is Incompatible: Kafka 409 Fix
Fix "Schema being registered is incompatible with an earlier schema; error code: 409" — why Schema Registry rejects your schema and how to evolve safely.
Kafka SaslAuthenticationException: Authentication Failed — Fix
Getting SaslAuthenticationException: Authentication failed in Kafka? Fix invalid SASL credentials, JAAS config, and missing SCRAM users with working examples.