standards-java

Java Coding Standards

Core Principles

1. Simplicity: Simple, understandable code
2. Readability: Readability over cleverness
3. Maintainability: Code that's easy to maintain
4. Testability: Code that's easy to test
5. SOLID: Follow SOLID principles for object-oriented design
6. DRY: Don't Repeat Yourself - but don't overdo it

General Rules

• Early Returns: Use early returns to avoid nesting
• Descriptive Names: Meaningful names for classes, methods, and variables
• Minimal Changes: Only change relevant code parts
• No Over-Engineering: No unnecessary complexity
• Immutability: Prefer immutable objects where possible
• Minimal Comments: Code should be self-explanatory. No redundant comments!

Naming Conventions

Element	Convention	Example
Classes	PascalCase	UserService, OrderRepository
Interfaces	PascalCase	UserRepository, PaymentProcessor
Methods	camelCase	getUserById, calculateTotal
Variables	camelCase	firstName, totalAmount
Constants	UPPER_SNAKE_CASE	MAX_RETRY_COUNT, DEFAULT_TIMEOUT
Packages	lowercase.dot.separated	com.example.service, com.example.repository
Test Classes	ClassNameTest	UserServiceTest, OrderRepositoryTest
Test Methods	descriptive_snake_case or camelCase	shouldReturnUserWhenIdExists

Project Structure

Maven Project

myproject/
├── pom.xml
├── src/
│   ├── main/
│   │   ├── java/
│   │   │   └── com/example/myapp/
│   │   │       ├── Application.java        # Main entry point
│   │   │       ├── config/
│   │   │       │   └── AppConfig.java      # Configuration
│   │   │       ├── domain/
│   │   │       │   └── User.java           # Domain models
│   │   │       ├── repository/
│   │   │       │   └── UserRepository.java # Data access
│   │   │       ├── service/
│   │   │       │   └── UserService.java    # Business logic
│   │   │       └── controller/
│   │   │           └── UserController.java # REST endpoints
│   │   └── resources/
│   │       ├── application.properties
│   │       └── application-dev.properties
│   └── test/
│       ├── java/
│       │   └── com/example/myapp/
│       │       ├── service/
│       │       │   └── UserServiceTest.java
│       │       └── repository/
│       │           └── UserRepositoryTest.java
│       └── resources/
│           └── application-test.properties
└── README.md