Can you explain what Reflection API is and what it is used for in programming?

Reflection API is a mechanism in programming languages (for example, in Java) that allows a program to obtain information about its classes, methods, fields, and even modify their behavior at runtime.

With Reflection, you can:

• Discover the structure of classes (names of methods, fields, constructors).
• Create objects dynamically.
• Invoke methods and get/set field values.

This is useful for frameworks that work with objects without knowing their types at compile time, such as serialization, dependency injection, testing.

Example of using Reflection in Java:

Class<?> clazz = Class.forName("java.lang.String");
Method method = clazz.getMethod("substring", int.class, int.class);
String str = "Hello, world!";
String result = (String) method.invoke(str, 7, 12); // "world"

Reflection is powerful but can reduce performance and break encapsulation, so it should be used cautiously.