Library Vs Framework

The difference between a library and a framework lies mainly in the control of flow and how they are used in your code.

📚 Library

➤ Definition:

A library is a collection of pre-written code that you can call and use whenever you need in your application.

➤ Key Characteristics:

You are in control: You call the library’s functions.
Focused on specific functionality (e.g., math, logging, database).
Can be used in any part of your code.

➤ Example:

In Java:

import java.util.ArrayList;

ArrayList<String> list = new ArrayList<>();
list.add("Hello");
list.add("World");

You call add() from the ArrayList library — you are in control.

🧱 Framework

➤ Definition:

A framework is a complete structure where your code fits in predefined places. The framework controls the flow and calls your code when needed.

➤ Key Characteristics:

Inversion of Control (IoC): The framework calls your code, not the other way around.
Provides a skeleton; you fill in the blanks.
Often used for larger systems (e.g., web apps, enterprise systems).

➤ Example:

In Spring Framework:

@RestController
public class HelloController {
    @GetMapping("/hello")
    public String sayHello() {
        return "Hello from Spring";
    }
}

Here, Spring controls the flow — it decides when and how to call sayHello().

🔁 Key Differences Summary

Feature	Library	Framework
Control Flow	You control the flow	Framework controls the flow
Usage	Call functions when needed	Plug your code into framework
Purpose	Specific functionality	Application structure
Examples (Java)	Apache Commons, Gson, JUnit	Spring, Hibernate, Java EE
Flexibility	More flexible	More rules and structure

🎯 Analogy

Library: A toolbox — you take the tools you need and use them however you want.
Framework: A machine — you insert your parts into the machine, and it runs the process.

Let me know if you want real-world code comparisons or help choosing between a framework and library for a specific project!