Could you explain what is meant by metadata and what role they play?

Metadata is data that describes other data. They provide additional information about the content, structure, properties, or context of data.

In Java, metadata is often implemented using annotations. Annotations allow adding information to classes, methods, fields, and other code elements, which can be used during compilation or runtime.

The role of metadata:

• Help tools and frameworks automatically process code (e.g., for serialization, validation, configuration).
• Improve code readability and maintainability by providing additional context.
• Enable declarative programming.

Example of an annotation in Java:

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface Test {}

public class Example {
    @Test
    public void testMethod() {
        // test method
    }
}

Here, @Test is metadata that can be used by a testing framework to detect and run tests.