Integration Testing with Testcontainers in Spring Boot 3
Write integration tests running on real PostgreSQL using Testcontainers and @ServiceConnection, share containers between test classes, and avoid common pitfalls.
Logging in Python: Production Configuration
Configure Python logging for production: per-module loggers, dictConfig, JSON logging, request_id with contextvars, QueueHandler, and testing with caplog.
Maps in Go and the concurrent map writes error
Learn how maps in Go work, why programs crash with "concurrent map writes", and how to fix it using sync.Mutex, sync.RWMutex, sync.Map.
Caching with @Cacheable and Redis in Spring Boot
Guide to using @Cacheable, @CachePut, @CacheEvict with Redis in Spring Boot 3, configuring TTL, JSON serializer, and writing tests with Testcontainers.
Collectors.groupingBy and partitioningBy Through Examples
Learn how to group and partition data using Collectors.groupingBy, partitioningBy, and downstream collectors like counting, mapping, filtering in Java 21.
pathlib instead of os.path: modern file path handling
Use pathlib.Path instead of os.path and os to join, split, read, write, and traverse files. Includes comparison table, pytest testing, and common mistakes.
Slices in Go: len, cap and append pitfalls
Understand how slices share a backing array, the role of len and cap, and how to avoid hard-to-detect data corruption bugs when using append.
Database Migration with Flyway in Spring Boot
Manage database schema with Flyway in Spring Boot 3. This article covers how to write SQL and Java migrations, configuration, testing, and handling common errors.
Go modules: managing dependencies and versioning
Guide to using Go modules for project initialization, adding and upgrading dependencies, handling major versions, replace, go.work, and private modules.
Proper Exception Handling in Python
How to use try/except/else/finally, define custom exceptions, raise from, logging, ExceptionGroup, and test exceptions with pytest.
Text Blocks and New String APIs (Java 15+)
Write multi-line strings more concisely with text blocks, master indentation and escape rules, and learn new String methods like formatted, stripIndent, and translateEscapes.
Generics in Java: Wildcards ? extends and ? super
Understand why List<Integer> isn't List<Number>, when to use ? extends, when to use ? super, and the PECS principle through concrete examples.
Pydantic v2: Input Data Validation in Python
How to use Pydantic v2 for input validation: BaseModel, Field, field_validator, model_validator, strict mode, TypeAdapter and testing with pytest.
Securing REST API with Spring Security and JWT
Configure Spring Security with JWT for REST API: issue tokens at login, stateless authentication, role-based authorization, and write tests with MockMvc.
Table-driven tests in Go
How to write table-driven tests in Go with slice structs, t.Run, error checking, parallel execution and struct comparison using go-cmp, plus common pitfalls.
FastAPI: Building REST API with Automatic Validation
Build REST API with FastAPI and Pydantic v2 to block invalid data at the entry point, customize 422 errors, and write tests with pytest.
Spring Boot Profiles: dev, test, prod Configuration
Separate configuration and beans by environment (dev, test, prod) using Spring Profiles, activate profiles in multiple ways, write tests with @ActiveProfiles, and avoid common pitfalls.
sync.WaitGroup, Mutex and errgroup: Coordinating Goroutines in Go
Use sync.WaitGroup to wait for goroutines, sync.Mutex to avoid data races, and errgroup to collect errors, cancel with context, and limit goroutine count.
try-with-resources and AutoCloseable in Java
How to use try-with-resources for automatic resource closing, writing your own AutoCloseable classes, understanding suppressed exceptions and common errors.
Building REST APIs with net/http using Go 1.22's new routing
Use Go 1.22's ServeMux to match HTTP methods, read path parameters, and return JSON. You'll have a complete REST API without needing third-party routers.