Backend 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.

Backend Aug 5, 2026 10 min read

Production Spring Boot Backend Systems Explained

Build a production-minded Spring Boot order service by separating HTTP, application, data, security, configuration, operations, testing, and incident-recovery layers.

Backend Aug 5, 2026 10 min read

Production Spring Boot Incident Troubleshooting

Troubleshoot Spring Boot incidents from evidence through reversible mitigation, rollback, and recovery verification across correctness, users, and resources.

Backend Aug 5, 2026 10 min read

Spring Boot Exception Handling Explained

Design safe Spring Boot error responses with ProblemDetail and RFC 9457 while respecting MVC, filter, security, async, and committed-response boundaries.

Backend Aug 5, 2026 10 min read

Spring Boot Request Validation Explained

Separate Spring Boot request-shape validation from authorization and concurrency-safe business invariants, including nested DTO and collection validation.

System Design Aug 4, 2026 11 min read

Database Query Performance for Backend Systems Explained

Learn how to diagnose database query performance using user impact, execution plans, planner estimates, I/O, locks, MVCC, connection pools, and safe production validation.

System Design Aug 4, 2026 10 min read

PostgreSQL EXPLAIN and Query Plans Explained

Learn to read PostgreSQL EXPLAIN plans safely, including costs, estimated and actual rows, loops, scans, joins, sorts, buffers, WAL, and production boundaries.

System Design Aug 4, 2026 10 min read

Query Planner Statistics and Cardinality Estimation Explained

Learn how query planners estimate rows using statistics, selectivity, histograms, most-common values, correlation, extended statistics, and production validation.

System Design Aug 2, 2026 11 min read

Backpressure, Bounded Queues, and Flow Control Explained

Control overload with explicit demand, bounded buffering, queue age, rejection, expiry, and end-to-end flow policies across APIs, streams, and brokers.

System Design Aug 2, 2026 10 min read

Bulkhead Pattern and Resource Isolation Explained

Contain backend failures by isolating concurrency, threads, connection pools, and queues across priorities, tenants, operations, and dependencies.

System Design Aug 2, 2026 10 min read

Graceful Degradation and Fallback Design Explained

Design explicit fallback modes that preserve business invariants, authorization, freshness contracts, and observable recovery under dependency failure.

System Design Aug 2, 2026 10 min read

Liveness, Readiness, and Startup Health Checks Explained

Design Kubernetes startup, liveness, and readiness probes that route safely, recover local deadlocks, and avoid overload-driven restart storms.

System Design Aug 2, 2026 11 min read

Production Resilience for Backend Systems Explained

Design backend systems that prevent, contain, degrade through, recover from, and verify failures while preserving user objectives and capacity.

System Design Aug 2, 2026 10 min read

Timeouts, Deadlines, and Cancellation Propagation Explained

Design end-to-end request budgets that distinguish hop timeouts, propagated deadlines, cooperative cancellation, and durable side effects under backend overload.

Algorithms Jul 25, 2026 8 min read

Bloom Filter Explained

Learn how Bloom filters trade small false-positive risk for compact membership checks, including sizing math, Java BitSet code, and backend use cases.

Backend Jul 2, 2026 5 min read

API Abuse Prevention Explained

Learn API abuse prevention for backend systems, including rate limits, authentication signals, quotas, bot patterns, logging, errors, and gateways.

Backend Jul 2, 2026 6 min read

API Authentication Best Practices

Learn API authentication best practices, including tokens, API keys, OAuth, mTLS, sessions, gateways, rotation, scopes, errors, and logging.

Backend Jul 2, 2026 5 min read

OAuth Client Credentials Flow Explained

Learn the OAuth client credentials flow for service-to-service APIs, including clients, secrets, scopes, tokens, rotation, and security risks.

Backend Jul 2, 2026 5 min read

Security Event Logging Explained

Learn security event logging for backend systems, including auth events, API abuse signals, safe metadata, alerting, retention, and mistakes.

Backend Jul 2, 2026 5 min read

Service Accounts Explained

Learn service accounts for backend systems, including machine identity, API access, least privilege, secrets, rotation, audit logs, and risks.

Backend Jul 1, 2026 6 min read

Audit Logs Explained for Backend Systems

Learn what audit logs are in backend systems, including actor, action, resource, timestamp, metadata, retention, privacy, and investigation workflows.

API Design Jul 1, 2026 5 min read

API Pagination Metadata Best Practices

Learn how to design pagination metadata for REST APIs, including pageInfo, cursors, hasNextPage, limits, totals, links, sorting, and compatibility.

System Design Jul 1, 2026 8 min read

Database Connection Pooling Explained

Learn database connection pooling for backend systems, including pool size, timeouts, leaks, max connections, queues, monitoring, and common mistakes.

System Design Jul 1, 2026 7 min read

Database Migration Rollback Explained

Learn database migration rollback strategies, including backward-compatible changes, expand-contract migrations, backups, deploy order, and recovery plans.

API Design Jul 1, 2026 5 min read

JSON Schema vs OpenAPI Schema

Compare JSON Schema and OpenAPI Schema for backend API contracts, including validation, documentation, examples, tooling, and compatibility.

Backend Jul 1, 2026 6 min read

Least Privilege Explained for Backend Developers

Learn the principle of least privilege for backend systems, including users, services, API keys, database roles, cloud permissions, and operational tradeoffs.

System Design Jul 1, 2026 6 min read

N+1 Query Problem Explained

Learn the N+1 query problem in backend apps, including ORM loading, SQL examples, eager loading, batching, joins, query counts, and fixes.

API Design Jul 1, 2026 6 min read

REST API Design Checklist

Use this REST API design checklist to review resources, methods, status codes, errors, pagination, idempotency, versioning, auth, and OpenAPI docs.

Backend Jul 1, 2026 6 min read

Secret Management Explained for Backend Developers

Learn secret management for backend apps, including environment variables, secret stores, rotation, least privilege, logging risks, and deployment workflows.

Backend Jul 1, 2026 5 min read

Spring Boot REST Controller Explained

Learn Spring Boot REST controllers, including @RestController, request mappings, DTOs, validation, status codes, error responses, and testing.

Backend Jun 30, 2026 5 min read

API Key Design Best Practices for Backend APIs

Learn practical API key design best practices, including key format, prefixes, hashing, scopes, rotation, rate limits, audit logs, and safe storage.

Backend Jun 30, 2026 5 min read

MFA Explained for Web Apps

Learn how multi-factor authentication works in web apps, including TOTP, WebAuthn, backup codes, recovery flows, step-up checks, and backend tradeoffs.

API Design Jun 30, 2026 4 min read

OpenAPI Explained for Backend Developers

Learn how OpenAPI describes REST APIs, including paths, operations, schemas, examples, auth, versioning, code generation, and contract review.

Backend Jun 30, 2026 5 min read

Password Hashing Explained for Backend Developers

Learn password hashing basics for backend systems, including salts, slow hashes, peppers, verification, resets, storage risks, and common mistakes.

API Design Jun 30, 2026 4 min read

PUT vs PATCH in REST APIs

Compare PUT and PATCH in REST APIs, including replacement vs partial updates, idempotency, validation, status codes, and backend implementation choices.

Backend Jun 30, 2026 4 min read

RBAC vs ABAC: Access Control Models Explained

Compare RBAC and ABAC for backend authorization, including roles, attributes, policies, ownership checks, tenant context, and practical tradeoffs.

Backend Jun 30, 2026 5 min read

Secure HTTP Headers Explained for Backend Developers

Learn practical secure HTTP headers for backend apps, including HSTS, CSP, X-Content-Type-Options, frame protection, referrer policy, and cookie-related limits.

Backend Jun 30, 2026 4 min read

Session Fixation Explained for Backend Developers

Learn what session fixation is, how it affects web authentication, why session rotation matters, and how backend teams can prevent it.

API Design Jun 30, 2026 5 min read

Webhook Signature Verification Explained

Learn how webhook signature verification works, including HMAC headers, raw request bodies, timestamps, replay protection, secret rotation, and safe failures.

API Design Jun 29, 2026 5 min read

API Gateway Explained

Learn what an API gateway does in backend architecture, including routing, authentication, rate limiting, observability, and tradeoffs.

System Design Jun 29, 2026 5 min read

Background Jobs Explained

Learn how background jobs work in backend systems, including queues, workers, retries, scheduling, idempotency, and monitoring.

Backend Jun 29, 2026 4 min read

Authorization vs Authentication

Compare authentication and authorization in backend systems, including identity checks, permissions, roles, scopes, sessions, tokens, and API enforcement.

System Design Jun 29, 2026 5 min read

Caching Strategies Explained

Learn common backend caching strategies, including cache-aside, write-through, write-behind, TTLs, invalidation, and cache stampede risks.

System Design Jun 29, 2026 5 min read

Circuit Breaker Pattern Explained

Learn how the circuit breaker pattern protects backend services from cascading failures, with closed, open, and half-open states.

Backend Jun 29, 2026 4 min read

CORS Explained for Backend Developers

Learn how CORS works for backend APIs, including origins, preflight requests, credentials, allowed headers, cookies, security limits, and common mistakes.

System Design Jun 29, 2026 6 min read

Database Sharding Explained

Learn what database sharding is, when backend systems need it, how shard keys work, and what tradeoffs sharding creates.

System Design Jun 29, 2026 5 min read

Database Transactions Explained

Learn what database transactions are, why ACID matters, how commits and rollbacks work, and what backend developers should know.

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 29, 2026 5 min read

Eventual Consistency Explained

Learn what eventual consistency means in distributed systems, why stale reads happen, and how backend teams design around them.

System Design Jun 29, 2026 5 min read

Load Balancing Explained

Learn how load balancing distributes traffic across backend servers, including algorithms, health checks, sticky sessions, and tradeoffs.

System Design Jun 29, 2026 5 min read

Message Queues Explained

Learn how message queues work in backend systems, including producers, consumers, retries, dead-letter queues, ordering, and idempotency.

API Design Jun 29, 2026 5 min read

REST API Error Handling Best Practices

Learn practical REST API error handling patterns, including status codes, stable error codes, field errors, request IDs, and safe messages.

System Design Jun 29, 2026 5 min read

Retry Patterns Explained

Learn safe backend retry patterns, including exponential backoff, jitter, retry budgets, idempotency, and when not to retry.

API Design Jun 29, 2026 4 min read

Webhooks Explained

Learn how webhooks work in backend systems, including event delivery, signatures, retries, idempotency, and common design mistakes.

API Design Jun 28, 2026 5 min read

API Versioning Explained

Learn practical API versioning strategies, including URL versions, header versions, backward compatibility, deprecation, and migration plans.

API Design Jun 28, 2026 5 min read

Rate Limiting in APIs Explained

Learn how API rate limiting works, including fixed windows, sliding windows, token buckets, 429 responses, headers, and backend tradeoffs.

Backend Apr 19, 2026 6 min read

OAuth 2.0 Explained for Backend Developers

A backend-focused OAuth 2.0 guide covering roles, authorization code flow, PKCE, scopes, tokens, client credentials, and common mistakes.