Author: anis kchaou

🏗️ Detailed Spring Security Flow Schema [1] HTTP Request │ ▼ ┌───────────────────────────┐ │ Security Filter Chain │ │ (DelegatingFilterProxy) │ └───────────────────────────┘ │ ▼ +----------------------------+ | Example Filters in Chain: | | - SecurityContextPersistenceFilter (loads SecurityContext) | | - UsernamePasswordAuthenticationFilter (handles login form) | | - BasicAuthenticationFilter (for Basic Auth) | | - BearerTokenAuthenticationFilter (for…

1. @Autowired Used for dependency injection (Spring automatically injects the required bean). By default, it matches by type. @Component class Engine { public String start() { return "Engine started"; } } @Component class Car { @Autowired private Engine engine; public void drive() { System.out.println(engine.start() + " - Car is driving"); } } @Component class…

Spring Boot + Resilience4j is a popular combo for building fault-tolerant, resilient microservices.Resilience4j provides resilience patterns like: CircuitBreaker – prevents cascading failures by stopping calls when downstream is unhealthy. Retry – automatically retries failed calls. RateLimiter – limits number of requests. Bulkhead – limits concurrent calls. TimeLimiter – sets timeouts for calls. ✅ Step…

🔹 What is Quartz? Quartz is a powerful, open-source job scheduling library. It lets you schedule tasks (jobs) to run: At a fixed interval At a specific time Using cron expressions 🔹 Add Quartz Dependency In a Spring Boot (Maven) project, include: <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-quartz</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-quartz</artifactId> </dependency> 🔹 Define a Quartz…

In Spring Boot, exception handling is usually done with the @ControllerAdvice and @ExceptionHandler annotations. This helps you catch exceptions globally and return proper responses (e.g., JSON error messages) instead of exposing stack traces. Here’s a simple example: 1. Create a Custom Exception package com.example.demo.exception; public class ResourceNotFoundException extends RuntimeException { public ResourceNotFoundException(String message) {…

Distributed tracing helps you follow a request as it flows through multiple microservices. It’s useful for: Debugging latency issues Understanding service dependencies Observing bottlenecks in request paths Traces are usually composed of spans: Trace ID: identifies the full request flow. Span ID: identifies a single operation within the trace. Parent Span ID: connects spans…

2. What is Spring Cloud Task? Spring Cloud Task is a microservice framework for creating short-lived, one-time tasks in a Spring Cloud environment. Unlike long-running services, tasks start, run, and finish. Typical use cases: Batch jobs Data migration scripts Event-driven tasks triggered by an event or schedule Key points: Each task is short-lived Can…

2. Spring Cloud Data Flow Overview Spring Cloud Data Flow (SCDF) is a microservices-based orchestration service for data integration and real-time data processing. It allows you to: Deploy streaming and batch data pipelines. Compose microservices (sources → processors → sinks). Monitor and manage applications at runtime. Key concepts: Source: Produces data (e.g., HTTP, Kafka,…

Prometheus is an open-source monitoring and alerting toolkit (part of the CNCF ecosystem). Supervision in this context usually refers to supervising processes or services using Prometheus. Prometheus collects metrics from services and systems, stores them, and lets you set up alerts (via Alertmanager) to supervise the health of your infrastructure. Example: CPU usage, memory…

1. Prerequisites Java 17+ Spring Boot 3.x RabbitMQ (running locally or via Docker) For RabbitMQ Docker: docker run -d --name rabbitmq -p 5672:5672 -p 15672:15672 rabbitmq:3-management docker run -d --name rabbitmq -p 5672:5672 -p 15672:15672 rabbitmq:3-management 5672 → RabbitMQ port 15672 → Management console 2. Add Dependencies In pom.xml (for Maven): <dependencies> <dependency> <groupId>org.springframework.boot</groupId>…