24. Reflection and Annotations
Reflection and Annotations are essential features in Java that enhance flexibility and extensibility. Reflection enables runtime inspection and manipulation of classes, methods, and fields, while annotations provide a metadata layer that aids compiler processing and runtime behavior. Understanding these core concepts, their use cases, advantages, and limitations is crucial for effective Java development, especially in modern frameworks and applications.
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What we have learnt
- Reflection allows a Java program to analyze and manipulate its runtime behavior and structure.
- Annotations serve as metadata that convey information to the compiler or runtime environment.
- Proper use of reflection and annotations can significantly improve the dynamic capabilities of Java applications.
Key Concepts
- -- Reflection
- The ability of a Java program to analyze and manipulate its runtime behavior, particularly the internal structure of classes, methods, and fields.
- -- Annotations
- Metadata in Java that provides information to the compiler or runtime without affecting the program semantics, often designated with the '@' symbol.
- -- Class Object
- An instance of java.lang.Class representing a loaded class in Java, which can be used to inspect its members at runtime.
- -- MetaAnnotations
- Annotations that define how other annotations should be treated, such as @Retention and @Target.
- -- Performance Overhead
- The slower performance of reflective calls compared to direct access due to runtime type checking.
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