Object-Relational Mapping (ORM) is a programming technique used to map data between an object-oriented programming language, such as Java, and a relational database system. ORM tools provide a way to persist data in a database using high-level object-oriented constructs and hide the details of database access and SQL statements from the developer.

In other words, ORM allows you to work with your data using objects instead of SQL statements, which can make your code more modular, easier to maintain, and more object-oriented. ORM frameworks typically provide a set of APIs and annotations that allow you to define the mapping between the database tables and the Java classes, as well as other features such as query generation, caching, and lazy-loading.

Some of the benefits of using ORM include:

• Reduced development time: ORM can simplify the data access layer of your application, which can reduce the amount of code you need to write and speed up development.

• Improved maintainability: ORM can make your code more modular and easier to maintain, by separating the business logic of your application from the database access layer.

• Increased portability: ORM can make your code more portable, by abstracting away the details of the underlying database system and allowing you to switch to a different database system without having to change the code.

• Reduced SQL errors: ORM can reduce the risk of SQL injection and other SQL errors, by automatically generating SQL statements and providing built-in protections against SQL injection attacks.

Some popular ORM frameworks in Java include Hibernate, EclipseLink, and OpenJPA. These frameworks provide a range of features and support for different database systems, and choosing the right ORM framework for your project depends on your specific requirements and needs.