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Setting Up Environment

Last Updated: December 5, 2025

7 min read

In this chapter, we will walk through the essential steps to set up a Java development environment on your machine, ensuring you have the right tools and configurations in place.

Installing the JDK

To start coding in Java, you need to install the Java Development Kit (JDK). The JDK includes everything you need to develop Java applications, including tools for compiling, debugging, and running your code.

Downloading the JDK

  1. Head over to the Oracle JDK download page or visit the OpenJDK website if you prefer an open-source version.
  2. Choose the version that matches your operating system (Windows, macOS, or Linux).
  3. Follow the installation instructions specific to your OS.

Installation Steps

  • Windows: Run the downloaded .exe file and follow the on-screen prompts. Make sure to check the box that says “Set JAVA_HOME variable” during installation if it's available.
  • macOS: Open the .dmg file and follow the installer instructions. You might need to set your JAVA_HOME manually afterward.
  • Linux: You can install the JDK using a package manager. For example, on Ubuntu, run:

Verifying the Installation

After installation, you can verify that the JDK is correctly set up:

  1. Open a terminal or command prompt.
  2. Type the following command:

If the installation was successful, you should see the version of Java you just installed.

Configuring the Environment Variables

Setting up your environment variables is an important step that allows your system to recognize the Java commands globally. This means you can compile and run Java programs from any directory.

Setting JAVA_HOME

Windows:

  1. Right-click on “This PC” or “Computer,” then select “Properties.”
  2. Click on “Advanced system settings,” then “Environment Variables.”
  3. Under “System variables,” click “New” and enter:
  4. Variable name: JAVA_HOME
  5. Variable value: Path to your JDK installation (e.g., C:\Program Files\Java\jdk-11.0.10)

macOS/Linux:

  1. Open your terminal and edit your shell configuration file (e.g., .bash_profile, .bashrc, or .zshrc).
  2. Add the following line, replacing the path with your JDK location:

To apply your changes, run:

Updating the PATH Variable

Next, you’ll want to add the JDK's bin directory to your system's PATH:

Windows:

  1. In the same Environment Variables window, find the Path variable under “System variables” and select it.
  2. Click “Edit” and add a new entry with the path to the JDK bin directory (e.g., C:\Program Files\Java\jdk-11.0.10\bin).

macOS/Linux:

  1. In the same shell configuration file, add the following line:

Save the file and run the appropriate source command again.

Verifying the Configuration

To check if your configurations are working:

  • Open a new terminal or command prompt and run:

You should see the path to your JDK installation. Also, running java -version should still yield the version of Java you installed.

Choosing an IDE

Now that your JDK is installed and configured, the next step is picking a suitable Integrated Development Environment (IDE). An IDE is a software application that provides comprehensive facilities to programmers for software development.

Popular IDEs for Java

  • IntelliJ IDEA: Often praised for its intelligent code assistance and ergonomic design, IntelliJ is a favorite among many developers. The Community Edition is free and open-source.
  • Eclipse: A powerful IDE with extensive plugin support, Eclipse has been around for years and continues to be widely used in enterprise environments.
  • NetBeans: A free and open-source IDE that provides great support for Java, especially for building web applications.

Installation

Each IDE has its installation procedure:

  • For IntelliJ IDEA: Download the installer from the JetBrains website and follow the prompts.
  • For Eclipse: Go to the Eclipse download page and download the installer. Run it and select “Eclipse IDE for Java Developers.”
  • For NetBeans: Visit the NetBeans download page and get the installer for your OS.

Setting Up Your IDE

After installing your chosen IDE, you’ll typically need to configure it to recognize your JDK installation:

  • IntelliJ IDEA: When you first launch IntelliJ, it will prompt you to configure the JDK. Simply point it to the Java installation directory.
  • Eclipse: Open Eclipse, go to “Window” > “Preferences” > “Java” > “Installed JREs”, and add your JDK.
  • NetBeans: During the first run, it will automatically detect your JDK. If not, you can set it manually in the configuration settings.

Writing Your First Java Program

Now that your environment is set up, it’s time to write your first Java program. This is a simple yet significant step in becoming familiar with the tools at your disposal.

Creating a New Project

  1. In IntelliJ IDEA: Click on “New Project,” select “Java,” and ensure your JDK is selected. Click “Next,” then name your project and finish the setup.
  2. In Eclipse: Go to “File” > “New” > “Java Project,” give it a name, and click “Finish.”
  3. In NetBeans: Click on “File” > “New Project,” select “Java” and then “Java Application.” Follow the prompts to create your project.

Writing a Simple Program

Here’s a classic example of a simple Java program that prints “Hello, World!” to the console:

Running Your Program

After writing the code, you’ll need to run it:

  • IntelliJ IDEA: Right-click on the file in the project explorer and select “Run ‘HelloWorld.main()’.”
  • Eclipse: Right-click on the file and select “Run As” > “Java Application.”
  • NetBeans: Click on the green “Run” button in the toolbar or right-click the file and choose “Run File.”

Congratulations! You’ve just compiled and run your first Java program.

Common Issues and Troubleshooting

As you begin your Java journey, you might encounter some common issues during setup. Here are a few troubleshooting tips:

PATH Issues

If you get a message saying java is not recognized as an internal or external command, it’s likely a PATH issue. Double-check that the bin directory of your JDK is correctly added to your system’s PATH.

IDE Configuration

Sometimes, your IDE might not detect the JDK. Ensure that:

  • You've set the JAVA_HOME variable correctly.
  • The IDE is pointed to the right JDK installation in its settings.

Version Conflicts

Ensure you're using a compatible JDK version with your IDE. For instance, some features in newer Java versions might not work in older IDE versions.

Now that you have successfully set up your Java environment, you are ready to explore your first Java program and see how everything comes together in practice.

In the next chapter, we will take a closer look at writing your first Java application, diving into the syntax and structure that makes Java unique.