Java

Casing Rules

Element	Convention	Example
Classes	PascalCase	OrderService, UserRepository
Interfaces	PascalCase	PaymentProcessor, UserRepository
Enums	PascalCase	PaymentMethod, OrderStatus
Enum constants	SCREAMING_SNAKE_CASE	CREDIT_CARD, IN_PROGRESS
Methods	camelCase	getUserById, processPayment
Variables	camelCase	userCount, isActive
Constants (static final)	SCREAMING_SNAKE_CASE	MAX_RETRY_COUNT, DEFAULT_TIMEOUT_MS
Packages	lowercase.dot.separated	com.acmeco.retail.orders

File Naming

One public class per file. The file name must match the class name exactly.

# Good:
OrderService.java
UserRepository.java
PaymentProcessor.java

# Test files mirror the source:
OrderServiceTest.java
UserRepositoryIT.java       # integration test suffix
OrderWorkflowE2ETest.java

Package Naming

Packages follow a reverse-domain hierarchy:

com.{company}.{org}.{solution}.{layer}

com.acmeco.retail.orders.service
com.acmeco.retail.orders.repository
com.acmeco.retail.orders.model

Keep packages lowercase with no underscores or hyphens. Each segment should be a single meaningful word.