How to use Custom Annotations with AOP in Spring Boot

🌀 Aspect-Oriented Programming (AOP) in Spring Spring AOP separates cross-cutting concerns like logging, transactions, and security from core business logic. It uses key concepts such as Aspect, Advice, Pointcut, and JoinPoint to define reusable behaviors. By modularizing these concerns, AOP makes code cleaner, maintainable, and easier to scale. 🧠 #SpringFramework #SpringBoot #Java #AOP #SoftwareEngineering #CleanCode #BackendDevelopment

Recently, I implemented Aspect-Oriented Programming (AOP) in my Spring Boot project to handle cross-cutting concerns like logging. Instead of adding repetitive logging code in every service method, I created a LoggingAspect using @Aspect and @Before advice. Now, I can automatically log method names and class details whenever any service method is called. This not only keeps the code clean and maintainable but also improves debugging and monitoring. 💡 Key Takeaways: AOP helps separate cross-cutting concerns from business logic. @EnableAspectJAutoProxy is crucial to enable AOP in Spring Boot. Proper pointcut syntax is important: even a missing space can prevent the aspect from triggering! Spring Boot + AOP = Powerful combination for clean, scalable, and maintainable code. #SpringBoot#AspectOrientedProgramming #Java #CleanCode #Logging #TechLearning

Custom Validation Annotations in Spring Boot: A Practical, Reusable Pattern 🚀 Custom validation annotations in Spring Boot unlock domain rules directly in your DTOs. To implement, you define a custom annotation with @Constraint and implement ConstraintValidator to encapsulate the logic. Add spring-boot-starter-validation to enable Bean Validation. For single-field checks, annotate the field. For cross-field checks (like password confirmation), create a class-level constraint and annotate the class. A practical pattern looks like this: - Annotation interface with message, groups, payload, and @Constraint(validatedBy = ...) . - Validator class implementing ConstraintValidator<YourAnnotation, TargetType> . - Apply the annotation on the target (field or class). Best practices: - Use meaningful messages and validation groups to control context. - Keep validators focused and test them in isolation, then wire them into controllers with @Validated/@Valid. Actionable steps: - Add the validation dependency. - Define your annotation. - Implement the validator. - Apply it to your DTO. - Test with both valid and invalid payloads. ❓ What custom validations have you built, or what tricky cross-field check would you tackle next? #SpringBoot #Java #BeanValidation #HibernateValidator #Validation

✨ Mastering Aspects Oriented Programming (AOP) in Spring / Spring Boot ✨ 🔹 Clean Code 🔹 Separation of Concerns 🔹 Reusable Cross-Cutting Logic 📌 What this diagram explains: 🧩 Business Method — Core application logic 🎯 Pointcut — Where the aspect will be applied 🛠️ Advices — ➤ @Before → Transaction Begins ➤ @After → Transaction Completes ➤ @AfterReturning → Transaction Committed ➤ @AfterThrowing → Transaction Rolled Back 🧱 Aspect — Cross-cutting transaction handling 🚀 AOP helps make applications more modular, maintainable, and cleaner by separating cross-cutting concerns like logging, security, and transactions. #SpringBoot #Java #AOP #BackendDevelopment #CleanCode #Programming

Why abstract class needs a constructor? 🤔 Even though you can’t create an object of an abstract class, its constructor still runs — because it helps initialize common properties when a subclass object is created! 🔥 💡 Example: The abstract class sets up base variables or logs setup info before the child class adds its own behavior. #Java #OOPs #Constructor #AbstractClass #JavaConcepts #CodingReels #Skillio #JavaForBeginners

#helloskillio Why abstract class needs a constructor? 🤔 Even though you can’t create an object of an abstract class, its constructor still runs — because it helps initialize common properties when a subclass object is created! 🔥 💡 Example: The abstract class sets up base variables or logs setup info before the child class adds its own behavior. #Java #OOPs #Constructor #AbstractClass #JavaConcepts #CodingReels #Skillio #JavaForBeginners https://lnkd.in/gWv63jaz

Day 5 – Learning Annotations in Spring Boot Today I learned how important annotations are in Spring Boot. They make the code shorter, cleaner, and easier to understand. Annotations I learned: • @RestController – Says this class will handle API requests • @RequestMapping – Gives a common path for all APIs in a class • @GetMapping / @PostMapping / @PutMapping / @DeleteMapping – Tell which method should run for each type of HTTP request • @Autowired – Automatically gives you the object you need • @Component / @Service / @Repository – Tell Spring to create and manage these classes These annotations are what make Spring Boot powerful and developer-friendly. #SpringBoot #Java #BackendDevelopment #LearningJourney

🚀 𝐃𝐚𝐲 9 𝐨𝐟 𝐦𝐲 #100𝐃𝐚𝐲𝐬𝐎𝐟𝐃𝐒𝐀 𝐉𝐨𝐮𝐫𝐧𝐞𝐲 𝐏𝐫𝐨𝐛𝐥𝐞𝐦𝐬 𝐒𝐨𝐥𝐯𝐞𝐝 𝐓𝐨𝐝𝐚𝐲 : 🔥 1️⃣ Leetcode (Medium) – Product of Array Except Self 💡 Key Idea: Instead of using division, use Prefix and Suffix Products. Prefix → product of all elements before the current index Suffix → product of all elements after the current index Multiply both to get the result for each element. 🧾 Time Complexity: O(n) ⚙️ Space Complexity: O(1) #DSA #Java #100DaysOfCode #ProblemSolving #LearningInPublic #SortingAlgorithms #CodingJourney

🔹 Day 39 – LeetCode Practice Problem: Perfect Number (LeetCode #507) 📌 Problem Statement: A perfect number is a positive integer that is equal to the sum of its positive divisors, excluding itself. Return true if the given number is perfect, otherwise return false. ✅ My Approach (Java): Initialize sum = 0. Iterate from 1 to num / 2. For every divisor i such that num % i == 0, add it to sum. After the loop, if sum == num, it’s a perfect number. 📊 Complexity: Time Complexity: O(n/2) Space Complexity: O(1) ⚡ Submission Results: Accepted ✅ Runtime: 2108 ms Memory: 41.19 MB 💡 Reflection: This problem reinforced the importance of divisor-based iteration. While this brute-force solution works, optimizing divisor checks using square roots can greatly improve performance — a good next step for refinement! #LeetCode #ProblemSolving #Java #DSA #CodingPractice #Learning

Today I learned something interesting about Spring Boot’s @Async annotation. I was debugging why an async method wasn’t actually running in parallel — and eventually realized it was because I was calling it from within the same class. Since the call never went through the Spring proxy, the @Async behavior didn’t trigger. Lesson: @Async only works when the method is invoked through a Spring-managed proxy — not via direct internal calls within the same bean. Moving the method to a separate service (or injecting the bean itself via a proxy) fixed it instantly. A small reminder that many “magic” framework features are really just smart proxies under the hood — and understanding how they work can save hours of debugging. Have you ever run into similar proxy or async surprises in Spring Boot? #TodayILearned #SpringBoot #Java #Microservices #BackendDevelopment #LearningInPublic