Installing Java JDK

Installing Java JDK (Java 17 LTS) for AP CS A

Introduction:

1. What is the JDK?
   • Java Development Kit.
   • A software package that provides the necessary tools, executables, and binaries to develop, compile, and run Java applications.
2. Why Do We Need JDK?
   • Essential for compiling Java programs.
   • Includes the Java Runtime Environment (JRE) to run Java applications.
   • Provides additional tools for development, debugging, and monitoring.
   • Includes the Java API documentation.
3. What is Java 17 LTS?
   • Java 17 is the latest long-term support (LTS) version of Java.
   • It is the recommended version for AP CS A.
   • It will be supported for several years.
   • It is the most stable version of Java.
   • It is the most widely used version of Java.
   • It is the most compatible version of Java.
   • It is the most secure version of Java.

Steps to Install Java 17 LTS JDK:

System Requirements Check

• Before starting the installation, ensure your computer meets the system requirements for the Java 17 JDK.
• The minimum requirements are:
  • 2 GB RAM
  • 2.5 GB disk space
  • 1280x800 screen resolution
  • Windows 8 or later, macOS 10.13 or later, Linux x64

Downloading

• Visit the official Oracle website or an alternative provider like AdoptOpenJDK.
• Navigate to the downloads section for Java 17 LTS.
• Download the appropriate JDK distribution for your operating system (Windows, MacOS, Linux).
• Choose the correct architecture (32-bit or 64-bit) for your system.
• Choose the correct package format (.exe, .dmg, .tar.gz, .rpm, etc.) for your system.

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Installation

Using Windows

• Launch the downloaded executable file.
• Follow the installation prompts, choosing the installation directory if needed (default is often suitable).
• Optionally, set up the JAVA_HOME environment variable.
• Optionally, add the bin directory of your JDK installation to the PATH variable.

Using MacOS

Using the .pkg file

• Open the downloaded .dmg file.
• Drag the JDK icon to the Applications folder.
• Optionally, set up the JAVA_HOME environment variable.
• Optionally, add the bin directory of your JDK installation to the PATH variable.

Using Homebrew

• Open a terminal.
• Install Homebrew if not already installed by running the command /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)".
• Run the command brew install --cask adoptopenjdk/openjdk/adoptopenjdk17.
• Optionally, set up the JAVA_HOME environment variable.
• Optionally, add the bin directory of your JDK installation to the PATH variable.

Using Linux

• Depending on the distribution format (.tar.gz or .rpm), use the appropriate method to install:
  • For .tar.gz: Extract the package and move it to the desired directory.
  • For .rpm: Use a package manager like yum or dnf to install.
• Optionally, set up the JAVA_HOME environment variable by editing the .bashrc file.
• Optionally, add the bin directory of your JDK installation to the PATH variable by editing the .bashrc file.

Verifying the Installation

• Open a terminal or command prompt.
• Type java -version and press Enter.
• The output should display the version number, confirming Java 17 is installed.
• Similarly, you can check the Java compiler with javac -version.

Setting Environment Variables in Windows (optional but recommended)

Verify Java Installation

• Open Command Prompt.
• Type java -version and press Enter.
• If Java is installed, the version will be displayed. Otherwise, you need to download and install the JDK.

Locate the Java Installation Directory

• Commonly, the JDK is installed in C:\Program Files\Java\jdk_version where jdk_version represents the version of the JDK.
• Make a note of this path.

Set the JAVA_HOME Environment Variable

• Right-click on This PC or Computer on the desktop or in File Explorer, then select Properties.
• Click on Advanced system settings on the left.
• Navigate to the Advanced tab and select Environment Variables.
• In the Environment Variables window, click New under the "System variables" section.
• For the Variable name, input JAVA_HOME.
• For the Variable value, enter the path you noted in step 2. For instance: C:\Program Files\Java\jdk_version.
• Click OK.

Add Java to the System PATH

• In the Environment Variables window (from Step 3), locate the Path variable under "System variables", then click Edit.
• In the Edit Environment Variable window, click New and enter the path %JAVA_HOME%\bin.
• Click OK on all open windows to close them.

Verify the Configuration

Open a new Command Prompt (close it first if one was already open). Type echo %JAVA_HOME% and press Enter. This should display the path of your JDK installation. Run java -version again to confirm that the system can identify the Java executable.

Tips and Considerations:

JRE vs JDK

• The JDK includes the JRE. Therefore, when you install the JDK, you can both compile and run Java applications.
• Separate JRE installations are usually not necessary unless you have specific requirements.

Multiple Versions

• It's possible to have multiple versions of Java on a single machine. Use the update-alternatives command on Linux or adjust the PATH variable on Windows/Mac to switch between versions.
• It's also possible to have multiple JDK versions on a single machine. However, only one version can be the default. Use the update-alternatives command on Linux or adjust the PATH variable on Windows/Mac to switch between versions.

Using a Package Manager

• On some platforms (like Linux), you can use package managers (like apt for Debian/Ubuntu or yum for Red Hat/Fedora) to install Java. This can simplify updates and multiple version management.

Licensing and Distribution

• Be aware of the licensing terms of the Oracle JDK. As of recent versions, Oracle introduced new subscription-based licensing for Oracle JDK, which might not be suitable for all use cases.

• Consider using alternative distributions like AdoptOpenJDK, Amazon Corretto, or others that may offer more favorable licensing terms or additional features.

Troubleshooting

• If you run into any issues during the installation, check the official documentation for troubleshooting tips.
• If you are still unable to resolve the issue, consider using an alternative distribution like AdoptOpenJDK or Amazon Corretto.

Conclusion:

Understanding how to properly install the JDK is essential for anyone looking to develop in Java. Java 17 LTS, being a long-term support version, will be a stable choice for several years. Once set up, students can begin compiling and running Java applications as part of their AP CS A coursework.