An environment setup is one of the prime parts before developing an application. To the developers who are currently working with Spring, feel free to skip this part. This section is for new developers, who need to set up the foundation and the instruments to begin developing.

Here are the steps of how to set up the environment in the accompanying segments.

Spring is the most powerful Java application framework; it is currently the most popular in the enterprise world. It helps to create high-performing applications that have easily-testable and reusable code. This is open source and was written by Rod Johnson, first released under the Apache 2.0 license in June 2003.

To create and run Spring applications, you need some tools and language supports. You also need a server to test and run your project in your operating system. We will show you how to set up the environment for Spring.

The following software and tools are needed with the current version:

• Java (version 1.8)
• Kotlin (version 1.3)
• Apache Tomcat (version 9.0.11)
• IntelliJ Ultimate (version 2018.2.2) or Eclipse Photon
• Spring Framework Libraries (version 5.0.8.RELEASE)

Java is available in two editions:

• Standard Edition (J2SE)
• Enterprise Edition (J2EE)

Here, we will opt for Standard Edition. Java is free to download and use for all operating systems.

You can download Java 10.0.2 from http://www.oracle.com/technetwork/java/javase/downloads/index.html.
Download for your operating system.

After installation, please check whether Java is installed. To check, open your Terminal and type java --version. If Java is installed successfully, you will see the following Java version:

Developed by JetBrains, Kotlin is an open source and statically-typed programming language. It runs on the Java Virtual Machine (JVM) and can be compiled to JavaScript source code or use the LLVM compiler infrastructure. Kotlin is easy to learn, especially for Java developers.

To use Kotlin, you don't need to download or set it up separately like Java. It comes with the IDEs. Kotlin is a built-in feature of Android Studio, IntelliJ Ultimate, or IntelliJ Community. To use Kotlin in Eclipse, you need to follow these steps:

1. Go to help -> Eclipse Marketplace from the Eclipse toolbar.
2. In the search box, write Kotlin, there you will find the Kotlin plugin.
3. Install it and you can write code in Kotlin:

We require a steady, free, and open source web server that we can use to create and run Spring-Framework-based ventures. We will utilize Apache Tomcat, which is easy to understand for all developers of Java. You can also use Jetty or Undertow to develop in Spring.

Tomcat is an open source web server. This allows the utilization of Java Servlets and JavaServer Pages (JSP) for the Java server. The core segment of Tomcat is Catalina.

You can download Tomcat 9.0.11 from https://tomcat.apache.org/download-90.cgi.

If you use Tomcat version 9, you have to use Java version 8 or later. According to the Apache Tomcat source, this version builds on Tomcat 8.0.x and 8.5.x, and implements the Servlet 4.0, JSP 2.3, EL 3.0, WebSocket 1.1, and JASPIC 1.1 specifications (the versions required by the Java EE 8 platform).

Let's see how to configure and verify the Tomcat server.

You can configure the Tomcat server in two ways—either using the Terminal or from the IDE. To set up the server, you have to download the Tomcat server's content from https://tomcat.apache.org/download-90.cgi.

Configuring Tomcat by these following steps:

1. Download a binary distribution of the core module from the link.
2. Extract the file. This creates a folder named apache-tomcat-9.0.11 (version number can be changed).

3. To access it with ease, rename the folder Tomcat and move it to /usr/local (for Linux) or /Library (for macOS):

• For Linux, use these steps:

// If you have an older version of Tomcat, then remove it before using the newer one
sudo rm -rf /usr/local/Tomcat        // To remove exist TomCat

sudo mv ~/Download/Tomcat /usr/local // To move TomCat from the download directory to your desire direction

• For macOS, use these steps:

// If you have an older version of Tomcat, then remove it before using the newer one
sudo rm -rf /Library/Tomcat            // To remove exist TomCat

sudo mv Downloads/Tomcat /Library/     // To move TomCat from the download directory to your desire direction

To check the current directory, type the following:

• For Linux: cd /usr/local/Tomcat/
• For macOS: cd /Library/Tomcat/

4. Type ls to see a list of this directory:

5. Change the ownership of the /usr/local/Tomcat or /Library/Tomcat folder hierarchy:

• For Linux: sudo chown -R <your_username> /usr/local/Tomcat/
• For macOS: sudo chown -R <your_username> /Library/Tomcat/

6. Make all scripts executable:

• For Linux: sudo chmod +x /usr/local/Tomcat/bin/*.sh
• For macOS: sudo chmod +x /Library/Tomcat/bin/*.sh

7. To check the contents of Tomcat, use the following command:

• For Linux: ls -al /usr/local/Tomcat/bin/*.sh
• For macOS: ls -al /Library/Tomcat/bin/*.sh

8. You can see that every file is listed with -rwxr-xr-x@, where -x means executable. Executable demonstrates to us the authorization status to get to the files:

9. To start and stop, type the following:

• For macOS:

/Library/Tomcat/bin/startup.sh
/Library/Tomcat/bin/shutdown.sh

• For Linux:

/usr/local/Tomcat/bin/startup.sh
/usr/local/Tomcat/bin/shutdown.sh

10. To turn on and off the Tomcat server, use this command:

1. After starting the server, go to your browser and enter http://localhost:8080, which will show you the default page:

This is how we can configure Tomcat from the Terminal.

When it comes to writing Java programs, you can use any text editor. However, we encourage you to use an integrated development environment (IDE) because they provide numerous features. IntelliJ IDEA, Eclipse, and NetBeans are the best of them. IntelliJ is a paid IDE, but you can use Eclipse or NetBeans, which are free.

We can use IDE to do the following:

• Manage Tomcat
• Develop apps and web apps where there is no need to remember the full name of the methods and signatures
• Highlight compile errors

In this book, we will work with Eclipse and IntelliJ IDEA.
You can download the Ultimate version, which has a 30-day free trial, from https://www.jetbrains.com/idea/download/.

To download the Eclipse, visit http://www.eclipse.org/downloads/packages/.

For Spring, you should download Eclipse IDE for the Java EE Developers version.

For both, once you start IDE, it will ask for a workspace. You can create a folder of your choice and give the path of that folder.

IntelliJ IDEA is a Java coordinated development environment for developing computer software. It is developed by JetBrains and is accessible as an Apache 2 Licensed people group release and in a restrictive business version. Both can be utilized for business development.

Eclipse is an incorporated development environment utilized in computer programming and is the most generally-utilized Java IDE. It contains a base workspace and an extensible module framework for tweaking the environment. Eclipse is composed generally in Java and its essential utility is for developing Java applications, yet it might likewise be utilized to develop applications in other programming dialects by means of modules, including Ada, ABAP, C, C++, C#, Clojure, COBOL, D, Erlang, Fortran, Groovy, Haskell, JavaScript, Julia, Lasso, Lua, NATURAL, Perl, PHP, Prolog, Python, R, Ruby (including the Ruby on Rails framework), Rust, Scala, and Scheme.

To use Kotlin in Eclipse, you will need to install the Kotlin plugin.

After creating a project, you’ll need to integrate the Tomcat server manually. However, if you use Spring Boot, you don't need to do anything because this comes with the Tomcat server.

Follow these steps to create a web project and implement the Tomcat server into your project:

1. Visit new > New Dynamic Web Project.
2. Provide a Project Name.
3. To integrate Tomcat, click New Runtime:

4. Download version 9+, select Apache Tomcat v9.0, and click Finish:

5. Select the latest Dynamic web module version.
6. Click Finish.

You will find these files after creating the project:

7. Go to the Server tab, which is in the bottom-left window:

8. Select Tomcat v9.0 Server at localhost.
9. Hit the start button.
10. Once the server is started, verify it by visiting http://localhost:8080 in a browser.
11. If everything is OK, you can start and stop the Tomcat server from here.