What are custom Java annotations and how do I create one?

What are custom Java annotations and how do I create one?

Custom Java annotations are a way to add metadata to your Java code. They can be used to provide information to the compiler or to be processed at runtime. To create one, you define an interface with the @interface keyword.

Can you give me an example of a custom annotation?

Sure! Here's a simple example:

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface MyCustomAnnotation {
    String value();
}

This annotation can be applied to methods and has a single element called value.

How do I use this annotation in my code?

You can use it like this:

@MyCustomAnnotation(value="Hello World")
public void myMethod() {
    // method implementation
}

Then, you can retrieve the annotation at runtime using reflection.

What is reflection in Java?

Reflection is a feature in Java that allows you to inspect classes, interfaces, fields, and methods at runtime, even if they are private. It enables dynamic behavior in your applications.