J4DB is a modern, lightweight, and fully type-safe JDBC abstraction layer for Spring Boot applications.

It automatically generates column enums from your database tables and provides a clean, fluent API for both raw and fully compile-time safe queries, as well as type-safe stored procedure calls.

• Automatic generation of type-safe XXXColumns enums implementing ColumnMeta
• Two powerful query APIs:
  • RawQuery — simple and flexible
  • TypedQuery — fully compile-time safe using QueryIn enums
• Type-safe stored procedure support (EnumBasedStoredProc, ProcIn / ProcOut)
• Excellent PostgreSQL support (UUID, JSONB, arrays, INET, etc.)
• Multi-database support via DatabaseDialect + DialectRegistry
• First-class support for Java Records (immutable entities)
• Lightweight core with minimal dependencies
• Spring Boot Starter with auto-configuration
• Ready for code generator

<dependency>
    <groupId>io.github.javaquasar</groupId>
    <artifactId>j4db-spring-boot3-starter</artifactId>
    <version>1.0.0-SNAPSHOT</version>
</dependency>

Gradle

implementation 'io.github.javaquasar:j4db-spring-boot3-starter:1.0.0-SNAPSHOT'

j4db:
  dialect: postgresql
  default-schema: public

@Service
@RequiredArgsConstructor
public class UserService {

    private final J4dbContext j4db;

    public List<User> findActiveUsers() {
        return j4db.query(UserRowMapper.class)
                .sql("SELECT * FROM users WHERE is_active = ?")
                .param(true)
                .executeList();
    }

    public User findById(Long id) {
        return j4db.typedQuery(UserRowMapper.class)
                .sql("SELECT * FROM users WHERE id = :userId")
                .param(UserQueryParams.USER_ID, id)
                .executeOneOrThrow();
    }
}

"Write SQL. Stay type-safe."

J4DB sits between raw JDBC and heavy ORMs — giving you full control over SQL while eliminating boilerplate mapping and stringly-typed parameters.

Roadmap

• Core runtime and EnumBasedRowMapper
• Raw & Typed Query API
• Stored Procedure support
• Code generator (tables → Columns enum + Mapper)
• Full Spring Boot auto-configuration
• Gradle & Maven plugins

This project is licensed under the Apache License 2.0 — see the LICENSE file for details.

Built with ❤️ for clean and maintainable Java backend development. Questions, suggestions, or contributions are welcome! Feel free to open an issue or pull request.