1. Introduction

This tutorial aims to introduce the Spring Framework, one of the most popular frameworks for building enterprise-grade applications in Java. We'll understand the core concepts, and set up a simple Spring project.

By the end of this tutorial, you'll learn:
- The basics of the Spring Framework
- How to set up a Spring project
- How to use Dependency Injection in Spring

Prerequisites:
- Basic understanding of Java
- Familiarity with any Integrated Development Environment (IDE) like IntelliJ IDEA or Eclipse
- JDK installed on your system

2. Step-by-Step Guide

2.1 Understanding Spring Framework

Spring Framework is a Java platform that provides comprehensive architecture and infrastructure support. It handles the infrastructure so you can focus on your application.

2.2 Setting up a Spring Project

We'll use Spring Initializr to create a new Spring project.

1. Visit https://start.spring.io/
2. Choose the following options:
3. Project: Maven
4. Language: Java
5. Spring Boot: The latest stable version
6. Fill in Project Metadata as desired
7. Click "Generate" to download your project

Unzip the downloaded file, and import it into your IDE as a Maven project.

2.3 Understanding Dependency Injection

At its core, Spring is a container that manages the lifecycle and configuration of application objects. These objects, known as beans in Spring parlance, are created with dependencies.

3. Code Examples

3.1 Creating a Bean

In Spring, you create a bean like this:

@Component
public class HelloBean {
    public String sayHello() {
        return "Hello, Spring!";
    }
}

@Component is a Spring annotation that marks this class as a bean.

3.2 Injecting a Bean

To use this bean in another class, you can do:

@Autowired
private HelloBean helloBean;

public void someMethod() {
    System.out.println(helloBean.sayHello());
}

@Autowired tells Spring to inject the instance of HelloBean into this class.

When you run the program, you should see Hello, Spring! printed on your console.

4. Summary

We've learned about the Spring Framework, set up a new Spring project, and seen how to create and use beans. Your next steps could be exploring more about Spring MVC for web applications, Spring Data for data access, or Spring Security for authentication and authorization.

5. Practice Exercises

1. Create a bean GoodbyeBean that has a method sayGoodbye() which returns "Goodbye, Spring!".
2. Inject the GoodbyeBean into another class and print the message.
3. Modify GoodbyeBean so that the goodbye message can be customized through a method parameter.

Solutions:

1. GoodbyeBean class:

@Component
public class GoodbyeBean {
    public String sayGoodbye() {
        return "Goodbye, Spring!";
    }
}

1. Injecting GoodbyeBean:

@Autowired
private GoodbyeBean goodbyeBean;

public void someMethod() {
    System.out.println(goodbyeBean.sayGoodbye());
}

1. Customizing GoodbyeBean:

@Component
public class GoodbyeBean {
    public String sayGoodbye(String msg) {
        return "Goodbye, " + msg;
    }
}

Inject and use:

@Autowired
private GoodbyeBean goodbyeBean;

public void someMethod() {
    System.out.println(goodbyeBean.sayGoodbye("Spring"));
}

These exercises will give you a good foundation in understanding how Spring works. Continue exploring more Spring features and happy coding!