Software Engineer's Blog

This guide provides a detailed walkthrough for integrating Swagger UI (with OpenAPI 3.0) into your Spring Boot project. It covers everything from initial dependency setup to handling authentication and following best practices to effectively automate and manage your API documentation. 1. Adding Dependencies First, add the necessary springdoc-openapi dependencies to your pom.xml file. springdoc-openapi-starter-webmvc-ui : This is the core library that automatically generates the OpenAPI 3.0 specification by analyzing your Spring Boot application. It also provides the embedded Swagger UI. springdoc-openapi-maven-plugin : (Optional) This plugin extracts the API documentation into a static file (e.g., openapi.json ) during the Maven build process. It's useful for CI/CD pipelines, sharing API specs with other teams, or generating client-side code. <dependencies> <dependency> <groupId>org.springdoc</groupId> <artifactId>s...

This blog guides you through the standard procedure for adding a gRPC endpoint to the order-service project. The primary goal is to handle "create new order" requests from external clients via gRPC. This process involves calling an internal u ser-service to validate user information. Why Use gRPC? Performance: It's fast, using HTTP/2 and binary serialization (Protobuf), which reduces communication overhead. Strict API Specification: The .proto file clearly defines the service interface and message structures, ensuring type safety at compile time. Multi-language Support: It's suitable for polyglot architectures, as clients and servers can be implemented in various languages. 1. Define the Service with Protocol Buffers (.proto) First, define the service contract by creating a .proto file in the src/main/proto directory. order.proto syntax = "proto3"; package com.abc.order.grpc; // Java code generation options option java_multiple_fil...

Lombok's @Builder is a powerful feature that replaces repetitive builder pattern code with a single annotation. However, when using @Builder , you might encounter the following warning message when you set an initial value for a field: java: @Builder will ignore the initializing expression entirely. If you want the initializing expression to serve as default, add @Builder.Default. If it is not supposed to be settable during building, make the field final. Why Does the Warning Occur? - How Lombok Works Before solving the problem, it's important to understand why Lombok ignores the initial value of the field. When a class is annotated with @Builder , Lombok generates a separate inner Builder class (e.g., UserBuilder ) at compile time. This is the class we use through the .builder() method. The key is that the fields of the original class and the fields of the Builder class exist in different spaces. import lombok.Builder; import lombok.Getter; @Getter @Builder pu...

Spring Boot Actuator provides a wide range of features to monitor and manage your application when it's deployed in a production environment. These features can be accessed via HTTP endpoints or JMX, and they automatically enable capabilities such as auditing, health checks, and metrics collection in your application. Actuator is essential in cloud-native and microservice architectures, allowing real-time monitoring of application status, metrics, and traffic data. In particular, the /actuator/health endpoint offers a basic mechanism to check if the application is running properly, making it crucial for integration with load balancers, Kubernetes, and other orchestration tools. Spring Boot Actuator Setup 1. Add Actuator Dependency pom.xml (maven) <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency> </dependencies...

In a microservice architecture, it's common for multiple services to share common functionality or utility classes. To handle this effectively, I manage these shared components as a reusable library (like libs.jar ) that each service can depend on. In this post, I’ll show you how I use GCP Artifact Registry to efficiently manage and distribute a shared library across microservices. Step 1: Enable the Artifact Registry API $ gcloud services enable artifactregistry.googleapis.com --project=[PROJECT_ID] Step 2: Create a Maven Repository in GCP Artifact Registry $ gcloud artifacts repositories create maven-repo \ --repository-format=maven \ --location=us-central1 \ --description="Shared Maven Repo for common libraries" $ gcloud artifacts repositories list --location=us-central1 REPOSITORY FORMAT LOCATION DESCRIPTION maven-repo MAVEN us-central1 Shared Maven repo Step 3: Configure pom.xml for the Shared Library Project In the share...

Spring Boot simplifies the process of accessing external configuration properties, like those defined in application.properties or application.yml, making it easier to maintain and change these properties without altering the codebase. A common approach to access these values is by using the @Value annotation in Spring-managed beans. However, sometimes developers encounter issues when trying to inject these values directly into their classes. The Problem Consider you have the following setup in your Spring Boot application: application.yml app: default-avatar-url: /images/twitter-default-avatar.jpg AuthServiceImpl.java import org.springframework.beans.factory.annotation.Value; import org.springframework.stereotype.Service; @Service public class AuthServiceImpl implements AuthService { @Value("${app.default-avatar-url}") private String defaultAvatarUrl; } However, when you run the application, you encounter a startup failure with the following error me...