Java Reflection @KonaTechAdda
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The document provides an overview of the Java Reflection API, including its design, key functionalities like accessing fields and methods at runtime, and examples of usage. It discusses necessary classes and various ways to obtain class information, as well as outlining drawbacks such as performance overhead and security concerns. References to articles and code snippets for further reading are included.
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Java Reflection @KonaTechAdda
- 1. Java Reflection API @KonaTechAdda Md Imran Hasan Hira Software Engineer Kona Software Lab Ltd. http://bd.linkedin.com/in/imranhasanhira https://www.facebook.com/KonaSoftware https://www.linkedin.com/company/kona-software-lab-ltd-
- 2. Outlines ⹠Design of reflection API ⹠Getting class ⹠Encoding class names ⹠Examples ⹠Modifiers ⹠Drawbacks What & Why ⹠Logics vs configurations ⹠Dependency Injections ⹠Methods param suggestion ⹠Build tools ⹠Spring⊠⹠Runtime Code generation ⹠Bytecode Manipulation
- 4. Basic Idea âą Accessing a field in runtime âą Find a class âą Instantiate a object form the class âą Find itâs field âą Set value of the field on that object âą Calling a method in runtime âą Find a class âą Instantiate a object form the class âą Find itâs method âą Invoke the method (with/without parameter) âą Get the returned value
- 6. âClassâ àŠà§àŠČàŠŸàŠ¶à§àŠ° public methods Class Including private Including Inherited Own + private, no inherited Own + inherited, except private
- 9. Ways to get class 1. With the static field* 2. Providing full class path 3. getClass() method
- 11. Finding fields upto superclass new Manager();
- 12. Data Parsing
- 14. Method Calling Name: Default name, Age: 0 Name: Dynamic name, Age: 0
- 15. JavaObject
- 16. Reflection Drawbacks âą Performance overhead âą Dynamically type resolutions occlude JVM optimizations. âą Should be avoided in parts of code in performance sensitive applications *Taken from a article of Dennis Sosnoski,
- 17. Reflection Drawbacks âą Performance overhead âą Dynamically type resolutions occlude JVM optimizations. âą Should be avoided in parts of code in performance sensitive applications âą Security Restrictions âą Requires a runtime permission, so your code may not run in a restricted security context. âą Exposure of Internals âą Accessing private fields and methods âą Reflective code breaks abstractions*
- 18. References Article from Oracle - https://docs.oracle.com/javase/tutorial/reflect/ http://docs.oracle.com/javase/8/docs/api/index.html?java/lang/Class. html Dennis Sosnoskiâs Article on Reflection - http://www.ibm.com/developerworks/java/library/j- dyn0603/index.html Source Code Snippets - https://github.com/imranhasanhira/java-reflection-annotation-test
- 19. Thank You ï