3.1 Lesson Outcomes

After completing this lesson, learners will be able to:

• Define REST API in Java.
• Explain the functions of REST API.
• Identify features of REST API.
• Explain the architecture and overview of REST APIs.
• Explain the role of Docker in launching MySQL environments.

3.2 Overview

REST API (Representational State Transfer Application Programming Interface) is a widely used architectural style for building web services and communication systems between applications. REST APIs allow applications to exchange information over HTTP using standard methods such as GET, POST, PUT, and DELETE.

This lesson introduces learners to REST API concepts, functions, features, architecture, and Docker integration in Java development environments.

REST APIs are widely used in:

• web applications,
• enterprise systems,
• cloud platforms,
• mobile applications,
• and distributed systems.

Understanding REST APIs is important because modern software systems rely heavily on web services and API-based communication.

KT0101 — Definition

REST API stands for:

Representational State Transfer Application Programming Interface

A REST API is a set of rules and conventions used to allow communication between:

• clients,
• servers,
• and applications

over HTTP.

REST API Characteristics

REST APIs:

• use HTTP protocols,
• are stateless,
• and exchange data between systems.

Common HTTP Methods

Importance of REST APIs

REST APIs support:

• communication,
• integration,
• and distributed application development.

KT0102 — Functions

REST APIs perform several important functions in software systems.

Functions of REST APIs

Example of REST API Request

GET /students

Example of REST API Response

JSON

[
{
“name”: “John”,
“age”: 20
}
]

Importance of REST API Functions

REST API functions improve:

• interoperability,
• scalability,
• and communication efficiency.

KT0103 — Features

REST APIs contain several important features used in modern software systems.

Features of REST APIs

Stateless Communication

Each request contains all information needed to process the request.

Example Resource URL

https://api.example.com/users

Importance of REST API Features

REST API features support:

• efficient communication,
• scalable applications,
• and flexible integration.

KT0104 — Understanding REST API – 10000 Feet Overview

REST APIs operate using:

• clients,
• servers,
• resources,
• and HTTP communication.

REST API Architecture Overview

Plain text

Client → HTTP Request → Server → HTTP Response

REST API Workflow

Common Data Formats

Example JSON Response

{
“id”: 1,
“name”: “Student”
}

Importance of REST Architecture

REST architecture improves:

• interoperability,
• distributed communication,
• and web service integration.

KT0105 — Using Docker to Launch MySQL – An Overview

Docker is a containerization platform used to run applications and services in isolated environments.

MySQL databases can be launched using Docker containers.

Docker Benefits

Example Docker Command

Plain text

docker run –name mysql-container
-e MYSQL_ROOT_PASSWORD=password
-p 3306:3306
-d mysql

MySQL in Docker

Docker allows developers to:

• deploy databases quickly,
• isolate environments,
• and simplify development setup.

Importance of Docker in Development

Docker supports:

• modern deployment,
• cloud development,
• and scalable application environments.

3.5 Key Notes / Summary

• REST API enables communication between applications.
• REST APIs use HTTP methods such as GET, POST, PUT, and DELETE.
• REST APIs are stateless and resource-based.
• JSON is commonly used for REST API responses.
• REST architecture supports scalable systems.
• Docker simplifies application and database deployment.
• MySQL databases can run inside Docker containers.