What are Java annotations and how do they work?

What are Java annotations and how do they work?

Java annotations are metadata that provide data about a program but are not part of the program itself. They can be used to give instructions to the compiler, provide information for tools, or influence the behavior of frameworks.

Can you give me some examples of built-in annotations?

Sure! Some common built-in annotations in Java include @Override, @Deprecated, and @SuppressWarnings. Each serves a specific purpose in the code.

How do I create a custom annotation?

To create a custom annotation, you define it using the @interface keyword. You can also specify retention policies and target elements.

What is the difference between @Retention and @Target?

@Retention specifies how long annotations are to be retained (e.g., source, class, runtime), while @Target specifies where the annotation can be applied (e.g., method, field, class).