Java

107 Posts

Java is both a programming language and a platform. Java's WRITE ONCE and RUN ANYWHERE is just too strong. Java is sleeker, faster, and much more powerful today.

Kafka 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.

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.

Kafka RetriableCommitFailedException: Causes and Fix

Kafka RetriableCommitFailedException on offset commit means a transient commit failure you must retry yourself. Here's what triggers it and how to handle it correctly.

Kafka: Assignments Can Only Be Reset If the Group Is Inactive

Kafka's reset-offsets fails with 'Assignments can only be reset if the group is inactive, but the current state is Stable.' Here's why, and the fix.