Custom annotations are user-defined annotations that you can create and apply in your Java programs to provide meaningful metadata. These annotations do not change the logic of the program but can be used to: Generate code at compile-time Perform validation at runtime Inject dependencies (used in frameworks like Spring) Support configuration and documentation Why Use …
The @Documented annotation is a meta-annotation in Java—meaning it is used to annotate other annotations.Its primary purpose is to ensure that custom annotations appear in the generated JavaDoc documentation. By default, annotations are not included in JavaDocs unless they are marked with @Documented. Purpose When you define a custom annotation and use @Documented on it, …
The @Override annotation in Java is a built-in marker annotation used to indicate that a method is intended to override a method in a superclass or implement an abstract method from an interface. This annotation helps the compiler catch errors during compilation when the method doesn’t actually override anything (due to typo, wrong signature, etc.) …
The @SuppressWarnings annotation in Java tells the compiler to ignore specific warnings that would otherwise be shown. It helps keep the codebase clean and avoids unnecessary clutter caused by harmless warnings. Purpose Suppress compiler warnings during compilation. Useful when you are aware of a situation that causes a warning but accept the risk or have …
The @Deprecated annotation in Java is used to indicate that a class, method, or field should no longer be used. It serves as a warning to developers that the annotated element is outdated, may be removed in future versions, and has a better alternative. Purpose Warn developers that a better approach exists. Encourage transition to …
Annotations in Java are metadata that provide information about the program but do not change the program’s behavior directly. They are processed either by the compiler or at runtime via reflection. Java provides several built-in annotations that are commonly used for: Compiler instructions Code analysis Runtime behavior customization What are Built-in Annotations? Built-in annotations are …
@Inherited is a meta-annotation in Java used to indicate that an annotation type is automatically inherited by subclasses of annotated classes. It is defined in the package: java.lang.annotation.Inherited By default, annotations are not inherited by subclasses. The @Inherited annotation allows custom annotations to be passed down from a superclass to its subclasses only if applied …
@Target is a meta-annotation (an annotation used on other annotations) in Java that specifies the kinds of program elements to which an annotation type is applicable.It is defined in the package java.lang.annotation.Target Why is it used? By default, a custom annotation can be applied to any program element—classes, methods, fields, parameters, etc. The @Target annotation …
@Retention is a meta-annotation in Java that is used to indicate how long annotations with this annotation are to be retained.It is defined in the java.lang.annotation package and is applied to other annotations. This helps the compiler or JVM understand whether the annotation should be discarded at compile time, retained in the class file, or …
Annotations are categorized based on their purpose, definition, and runtime availability. Below is a detailed explanation of Annotation Types in tabular format with examples. Code Snippet for Each Annotation Type 1.Marker Annotation 2.Single-Value Annotation 3.Multi-Value Annotation 4.Custom Annotation Declaration 5.Meta-Annotation Annotations in Java provide a powerful way to add metadata to your code, which can …
