Reflection Basics

Reflection is a Java feature that allows an executing program to inspect, modify, and instantiate classes, methods, fields, and constructors at runtime, bypassing compile-time type checking.

Reflection Capabilities and Trade-offs

• Access Bypassing: You can call setAccessible(true) on fields/methods to read or execute private class members.
• Performance Overhead: Because types are resolved dynamically at runtime, JVM JIT compiler optimizations (like method inlining) are bypassed, making reflection slow.
• Type Safety Risks: Bypassing compiler checks increases the risk of runtime exceptions (like NoSuchMethodException).

Code Walkthrough

This program demonstrates how reflection can inspect class names dynamically at runtime.

public class ReflectionBasicsDemo {
    public static void main(String[] args) throws ClassNotFoundException {
        // Retrieve class metadata dynamically
        Class clazz = Class.forName("java.lang.String");
System.out.println("Class Name: " + clazz.getName());
        System.out.println("Is Interface? " + clazz.isInterface());
    }
}

Interview-Relevant Information