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 predefined annotations provided by the Java language in the java.lang and java.lang.annotation packages. These annotations are ready to use and commonly used in development, testing, and API design.
Classification of Built-in Annotations
1. Compiler-Level Annotations
These annotations instruct the compiler to enforce certain checks or optimizations.
2. Meta-Annotations
These are annotations applied to other annotations (annotation types). They are used to define annotation behavior.
Java’s built-in annotations are powerful tools for code documentation, compiler interaction, and runtime behavior customization. Mastering these annotations is essential for writing clean, maintainable, and efficient Java applications.