Free Udemy Course 2025: Java Reflection API - Free Udemy Course [100% Off]

Mastering the Java Reflection API is a critical step for any developer aiming to understand the inner workings of modern Java frameworks like Spring, Hibernate, or JUnit. This comprehensive practice exam course is specifically designed to bridge the gap between theoretical knowledge and practical application.Welcome to the best practice exams to help you prepare for your Java Reflection API - Practice Questions 2026. This course provides a deep dive into the dynamic capabilities of the Java language, ensuring you are prepared for technical interviews, certification exams, and complex enterprise development tasks.Why Serious Learners Choose These Practice ExamsSerious learners choose this course because it goes beyond simple rote memorization. Our question bank is meticulously crafted to challenge your understanding of how classes, methods, and fields are manipulated at runtime.Retakeability: You can retake the exams as many times as you want to ensure mastery.Original Question Bank: This is a huge, original question bank updated for the latest Java standards.Expert Support: You get support from instructors if you have questions regarding any concept.Detailed Insights: Each question has a detailed explanation to facilitate learning from mistakes.Flexibility: Mobile-compatible with the Udemy app for learning on the go.Risk-Free: 30-days money-back guarantee if you're not satisfied.Course StructureThe exams are organized into a logical progression to help you build confidence as you move from basics to architectural implementation:Basics / Foundations: Focuses on the java.lang.Class object. You will learn how to obtain class instances using .class syntax, getClass(), and Class.forName(), while understanding the fundamental entry points of the API.Core Concepts: This section covers the inspection of class members. You will be tested on identifying constructors, methods, and fields, including the differences between public and declared members.Intermediate Concepts: Here, we dive into dynamic manipulation. Questions focus on the AccessibleObject API, changing field values at runtime, and invoking methods dynamically using the invoke() method.Advanced Concepts: This module covers complex topics such as dynamic proxies, handling generic type information at runtime, and interacting with annotations via reflection.Real-world Scenarios: Practice how reflection is used in the industry to build custom dependency injection containers, object-relational mapping (ORM) tools, and automated testing frameworks.Mixed Revision / Final Test: A comprehensive simulation of a professional assessment, pulling questions from all previous sections to test your retention and speed.Sample Practice QuestionsQUESTION 1Which method should be used to access a private field named "salary" that is defined specifically in the current class, but not in its superclasses?Option 1: getField("salary")Option 2: getFields("salary")Option 3: getDeclaredField("salary")Option 4: getDeclaredFields("salary")Option 5: getPrivateField("salary")CORRECT ANSWER: Option 3CORRECT ANSWER EXPLANATION: getDeclaredField(String name) returns a Field object that reflects the specified declared field of the class or interface represented by this Class object. This includes public, protected, default, and private fields, but excludes inherited fields.WRONG ANSWERS EXPLANATION:Option 1: getField() only returns public fields. It will throw a NoSuchFieldException if the field is private.Option 2: getFields() returns an array of all public fields, it does not take a String argument to find a specific field.Option 4: getDeclaredFields() returns an array of all fields declared in the class; it does not take a String argument for a specific name.Option 5: There is no method named getPrivateField in the Java Reflection API.QUESTION 2What is the primary purpose of calling setAccessible(true) on a Method object?Option 1: To make the method public in the source code.Option 2: To bypass Java language access control checks for that specific object.Option 3: To allow the method to be inherited by subclasses.Option 4: To increase the execution speed of the method invocation.Option 5: To compile the method into bytecode at runtime.CORRECT ANSWER: Option 2CORRECT ANSWER EXPLANATION: The setAccessible(true) method indicates that the reflected object should suppress Java language access checking when it is used. This allows a developer to invoke private methods or access private fields.WRONG ANSWERS EXPLANATION:Option 1: Reflection does not modify the source code or the permanent modifiers of the class.Option 3: Accessibility for inheritance is determined by the Java Language Specification and modifiers, not the Reflection API.Option 4: setAccessible(true) can slightly improve performance by skipping checks, but its "primary purpose" is access, not optimization.Option 5: Compilation is handled by the JIT compiler or javac, not by setting accessibility.QUESTION 3Which of the following is the correct way to instantiate a class named "com.test.User" using its default no-argument constructor via reflection?Option 1: Class. forName("com.test.User"). newInstance()Option 2: new User()Option 3: Class. forName("com.test.User"). getConstructor().newInstance()Option 4: Class. load("com.test.User"). create()Option 5: User. class. build()CORRECT ANSWER: Option 3CORRECT ANSWER EXPLANATION: While Class. newInstance() was used in older versions of Java, it is now deprecated. The modern and preferred approach is to get the constructor object and call newInstance() on it. This handles exceptions more effectively.WRONG ANSWERS EXPLANATION:Option 1: This method is deprecated since Java 9 because it propagates checked exceptions unnecessarily.Option 2: This is standard instantiation, not reflection.Option 4: Class. load and .create() are not valid methods in the standard Reflection API.Option 5: .build() is not a method available on the Class object.We hope that by now you're convinced! And there are a lot more questions inside the course to help you master every nuance of the dynamic capabilities of Java.