[Java] Entity4j - Lightweight Java ORM

[Quackster]

Entity4j - Lightweight Java ORM

GitHub Repository (full documentation)

What is Entity4j?
A minimal, type-safe Object Relational Mapper (ORM) for Java inspired by Entity Framework. Built and tested on Java 1.8 with support for MySQL, PostgreSQL, SQL Server, and SQLite.

Key Features:
• Lambda-based queries - Type-safe filtering with method references
• Annotation-based entities - Simple @Entity, @Id, @Column mapping
• Fluent mappings - Alternative to annotations for complex configurations
• Auto table creation - Generate tables from entity classes
• Multi-dialect support - Works with major databases
• Column selection - Project only needed columns for performance
• CRUD operations - Full Create, Read, Update, Delete support
• Bulk operations - Filtered updates and deletes without loading entities

Quick Example:

// Define entity
@Entity(table = "users")
public class User {
    @Id(auto = true) private Long id;
    @Column(name = "full_name", nullable = false) private String name;
    private Boolean active;
}

// Query with lambdas
List<User> results = ctx.from(User.class)
    .filter(f -> f.equals(User::getActive, true))
    .orderBy(User::getName, true)
    .limit(10)
    .toList();

Installation:
Gradle:

repositories { maven { url 'https://jitpack.io' } }
dependencies { implementation 'com.github.lovepigeons:Entity4j:v1.0.5' }

Maven:

<repository><id>jitpack.io</id><url>https://jitpack.io</url></repository>
<dependency>
    <groupId>com.github.lovepigeons</groupId>
    <artifactId>Entity4j</artifactId>
    <version>v1.0.5</version>
</dependency>

Advanced Features:
• Complex filtering with AND/OR logic and parentheses
• JOIN support with column selection into custom DTOs
• Pagination with limit/offset
• Multi-column ordering
• SQL debugging and parameter output
• Both annotation and fluent mapping styles

Perfect for developers who want Entity Framework-like functionality in Java without the complexity of heavyweight ORMs like Hibernate.