1. What is Spring?

Spring is a Java framework used to build enterprise/backend applications.

Its biggest features are:

• Dependency Injection
• Inversion of Control
• Spring Beans
• Modular architecture
• Support for web applications, databases, security, etc.

The important idea is:

Spring manages objects and their dependencies for you.

2. What is Spring Boot?

Spring Boot is built on top of Spring and makes creating Spring applications much easier.

It provides:

• Auto-configuration
• Starter dependencies
• Embedded servers
• Minimal configuration
• Production-ready features

For example, with Spring Boot you can create a web application and run it directly without manually deploying it to an external Tomcat server.