Hello, dear Jetto Net followers!

Welcome to our Java OOP series. Today, we will be exploring annotations used in Java.

What is an Annotation?

Annotations are special markers that we can add to our code. These markers provide information to the compiler, other tools, or the runtime environment about the code. Annotations do not change the functionality of the code, but they can influence how the code is interpreted or used.

Annotations begin with the @ symbol, followed by the name of the annotation. They can be applied to classes, interfaces, methods, variables, and even other annotations.

Built-in Annotations

Java provides several built-in annotations. Some of the most commonly used ones include:

• @Override: Indicates that a method overrides a method from its superclass.
• @Deprecated: Marks a class, method, or variable as outdated and advises against its use.
• @SuppressWarnings: Suppresses specific warnings that might otherwise be shown by the compiler.

Creating Custom Annotations

We can also create our own custom annotations. Custom annotations are defined using the @interface keyword.

public @interface Author { String name(); String date(); }

In the example above, I defined an annotation named Author. This annotation has two elements: name and date.

Use Cases for Annotations

Annotations can be used for various purposes in a program:

• Instructing the Compiler: Annotations can be used to instruct the compiler on how to handle certain code. For example, the @Override annotation tells the compiler that a method overrides a method in the superclass.
• Providing Runtime Information: Annotations can embed information in the code that will be used at runtime. For instance, a web framework might use the @RequestMapping annotation to determine which method should respond to a specific URL request.
• Code Analysis and Documentation: Code analysis tools and documentation generators can use annotations to better understand and interpret the code.

Conclusion

Annotations are a powerful tool in Java that allow us to add metadata to our code. By using annotations, we can better document our code, provide additional information to the compiler and other tools, and embed data to be used at runtime.

In the next article, we will continue to explore other important concepts of OOP. Feel free to leave your questions or comments below.

Happy Coding!