Concurrency Articles | Backend Study Lab

Java Aug 18, 2026 4 min read

CompletableFuture Composition, Errors, and Timeouts

Compose Java CompletableFuture stages deliberately across executors, failures, timeouts, cancellation, context, and external side-effect boundaries.

Java Aug 18, 2026 5 min read

Java Concurrency for Backend Systems Explained

Build a practical model of tasks, threads, shared state, race conditions, thread safety, and bounded concurrency in Java backend services.

Java Aug 18, 2026 6 min read

Java Concurrency Budget Lab: Queues, Virtual Threads, and Cancellation

Run six deterministic Java concurrency scenarios to compare fixed pools, virtual threads, resource guards, deadlines, and cooperative cancellation.

Java Aug 18, 2026 4 min read

ExecutorService, Thread Pools, and Work Queues in Java

Design Java executors around admission, worker, queue, rejection, shutdown, and downstream capacity instead of treating threads as free throughput.

Java Aug 18, 2026 4 min read

Java Interruption, Cancellation, and Deadlines Explained

Propagate Java interruption and request deadlines cooperatively across executors, blocking calls, cleanup, Spring boundaries, and durable effects.

Java Aug 18, 2026 4 min read

Java Memory Model, Visibility, and Happens-Before Explained

Understand atomicity, visibility, ordering, data races, volatile fields, safe publication, and happens-before reasoning in Java backend code.

Java Aug 18, 2026 4 min read

Scoped Values and Structured Concurrency in Modern Java

Separate Java 25 Scoped Values from JDK 26 preview Structured Concurrency and reason about bounded context, task lifetime, failure, and cancellation.

Java Aug 18, 2026 5 min read

Java Virtual Threads for Backend Services

Use Java 21 virtual threads for blocking backend tasks while keeping CPU, connection pools, downstream limits, context, and pinning explicit.

Java Aug 18, 2026 5 min read

Production Java Concurrency Troubleshooting

Diagnose Java thread starvation, unbounded queues, lock contention, virtual-thread pinning, downstream overload, and failed cancellation with evidence.

Java Aug 18, 2026 5 min read

synchronized, Locks, and Atomic Variables in Java

Compare Java monitors, ReentrantLock, CAS, atomic variables, lock scope, fairness, and compound invariants through backend examples.

System Design Aug 4, 2026 11 min read

Database Lock Contention and Long Transactions Explained

Learn to diagnose PostgreSQL lock contention, blockers, waiters, long transactions, idle-in-transaction sessions, pool exhaustion, and safe cancellation.

API Design Jul 26, 2026 6 min read

ETag and Conditional Requests Explained

Implement ETag, If-None-Match, Last-Modified, 304 responses, and safe update preconditions with Spring Boot and Express examples.

System Design Jul 25, 2026 9 min read

Database Deadlocks Explained

Learn why database deadlocks happen, how PostgreSQL and MySQL detect them, and how to prevent and retry them safely in Java and Node.js.

System Design Jul 25, 2026 9 min read

Database Isolation Levels Explained

Compare database isolation levels, concurrency anomalies, PostgreSQL and MySQL behavior, and safe Spring and Node.js transaction patterns.

System Design Jun 29, 2026 4 min read

Distributed Locks Explained

Learn what distributed locks are, when backend systems use them, why they are risky, and what safer alternatives to consider.

System Design Jun 28, 2026 5 min read

Optimistic Locking Explained

Learn how optimistic locking prevents lost updates in backend systems using version columns, compare-and-swap updates, and 409 conflicts.

Java Mar 15, 2026 4 min read

ConcurrentHashMap Explained

A practical explanation of ConcurrentHashMap in Java, including thread safety, atomic methods, iteration behavior, and common mistakes.

Java Jan 8, 2026 4 min read

HashMap vs Hashtable in Java: Key Differences

Compare HashMap and Hashtable in Java, including synchronization, null keys, performance, legacy status, and modern alternatives.