Creating Custom Annotations in Spring Boot

Annotations in Java and Spring Boot provide a powerful way to add metadata and behavior to your code. While Spring provides many built-in annotations, you might need to create your own custom annotations to enforce business rules, handle validation, or manage configurations. This blog post will guide you through creating and using custom annotations in Spring Boot.

1. Understanding Annotations in Java

Annotations in Java are metadata that provide information about the code but do not directly affect execution. They can be processed at compile-time or runtime, depending on their retention policy.

Java provides three key meta-annotations to define custom annotations:

• @Target: Specifies where the annotation can be applied (e.g., class, method, field).
• @Retention: Defines whether the annotation is available at runtime or only at compile time.
• @Documented: Indicates that the annotation should be included in Javadoc.
• @Inherited: Specifies that the annotation can be inherited by subclasses.

2. Creating a Custom Annotation in Spring Boot

Let’s create a custom annotation that validates if a string field contains only…