What are Java annotations and how does reflection work with them?

What are Java annotations and how does reflection work with them?

Java annotations are metadata that provide data about a program but are not part of the program itself. Reflection allows you to inspect and manipulate these annotations at runtime.

Can you give me an example of how to use annotations in Java?

Sure! You can create a custom annotation like @MyAnnotation and then use it on classes or methods. For example:

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

Then, you can use reflection to read this annotation at runtime.

How do I access the annotation values using reflection?

You can access annotation values using the getAnnotation method from the Method class. For example:

Method method = MyClass.class.getMethod("myMethod");
MyAnnotation annotation = method.getAnnotation(MyAnnotation.class);
String value = annotation.value();