How to Install Java 8 on Linux: A No-Nonsense Guide
Installing Java 8 on Linux might seem like a trip back to the past in our world of ever-evolving technology. However, many legacy applications and development environments still rely on this stalwart version. This guide provides a clear, concise, and practical approach to getting Java 8 up and running on your Linux system, regardless of your distribution.
The core of the installation boils down to these steps: Download the Java 8 JDK or JRE, extract the archive, configure your environment variables, and verify the installation. I’ll unpack each of these steps in excruciating detail, so you won’t miss a beat.
Step-by-Step Installation Process
1. Obtaining the Java 8 Package
The first hurdle is getting your hands on the correct package. Oracle, the original vendor, requires you to have an account and accept their license agreement to download Java 8.
- Oracle JDK: Navigate to the Oracle Java SE 8 Archive Downloads page. You’ll need an Oracle account to proceed. Choose the appropriate Linux version (e.g.,
.tar.gzfor most distributions). - AdoptOpenJDK/Eclipse Temurin: A more open and user-friendly approach is to use a pre-built package from AdoptOpenJDK (now Eclipse Temurin). They offer builds of OpenJDK, which is the open-source implementation of Java. Head over to the Eclipse Temurin downloads page and grab the Java 8 JDK or JRE package suitable for your system architecture (x64 is common).
Expert Tip: I strongly recommend Eclipse Temurin. It simplifies the process considerably and aligns with modern open-source principles. Plus, the performance is typically identical to Oracle’s JDK.
2. Extracting the Downloaded Archive
Once you’ve downloaded the .tar.gz file (whether from Oracle or Eclipse Temurin), it’s time to extract it. I usually prefer placing Java installations in the /opt directory, but you can choose another location if you prefer.
sudo mkdir -p /opt/java sudo tar -xzf <your_downloaded_file>.tar.gz -C /opt/java Replace <your_downloaded_file>.tar.gz with the actual name of the downloaded archive. The sudo commands ensure you have the necessary permissions to create the directory and extract the files. The -p flag in mkdir ensures parent directories are created if they don’t exist.
3. Configuring Environment Variables
This is where the magic happens. Configuring your environment variables tells your system where to find the Java installation.
Find the Java Directory: First, identify the exact directory where the Java files were extracted. Assuming you used the previous command, it will be something like
/opt/java/jdk1.8.0_XXXor/opt/java/temurin8. TheXXXrepresents a version number, so replace it with your specific installation.Set JAVA_HOME: The
JAVA_HOMEenvironment variable points to the root directory of your Java installation. You can set it temporarily for the current session or permanently by modifying your shell configuration file (e.g.,.bashrcor.zshrc).Temporary (Current Session):
export JAVA_HOME=/opt/java/jdk1.8.0_XXX export PATH=$PATH:$JAVA_HOME/binPermanent (Edit
.bashrcor.zshrc):nano ~/.bashrc # Or nano ~/.zshrc, depending on your shellAdd the following lines to the end of the file:
export JAVA_HOME=/opt/java/jdk1.8.0_XXX export PATH=$PATH:$JAVA_HOME/binSave the file and exit the editor. Then, source the file to apply the changes:
source ~/.bashrc # Or source ~/.zshrc
Alternative: Using
alternatives(For Debian-based systems): On Debian-based distributions (like Ubuntu), you can use thealternativescommand to manage Java installations:sudo update-alternatives --install "/usr/bin/java" "java" "/opt/java/jdk1.8.0_XXX/bin/java" 1 sudo update-alternatives --install "/usr/bin/javac" "javac" "/opt/java/jdk1.8.0_XXX/bin/javac" 1 sudo update-alternatives --install "/usr/bin/javaws" "javaws" "/opt/java/jdk1.8.0_XXX/bin/javaws" 1Then, select the Java version:
sudo update-alternatives --config java sudo update-alternatives --config javac sudo update-alternatives --config javawsThis method is generally preferred on Debian systems as it handles version switching more gracefully.
Expert Tip: Always use the full, absolute path for
JAVA_HOME. Avoid relative paths, as they can cause issues.
4. Verifying the Installation
Now, let’s confirm that Java 8 is installed correctly. Open a new terminal (or re-source your shell configuration) and run the following commands:
java -version javac -version The output should display the Java 8 version information. If you see an error message or a different Java version, double-check your environment variables and ensure they point to the correct Java 8 directory.
Expert Tip: If you have multiple Java versions installed, the
java -versioncommand might display a different version than you expect. This is where thealternativescommand on Debian-based systems really shines, allowing you to easily switch between versions.
Frequently Asked Questions (FAQs)
1. Why do I need to create an Oracle account to download Java 8?
Oracle’s licensing terms require users to have an account and accept their agreement before downloading Java 8. This is a change from their earlier practices. The Eclipse Temurin option provides a readily accessible alternative without these requirements.
2. What’s the difference between JDK and JRE?
The JDK (Java Development Kit) is for developers and includes the tools needed to compile, debug, and run Java applications. The JRE (Java Runtime Environment) is for running Java applications. If you only need to run Java programs, the JRE is sufficient. However, if you plan to develop Java applications, you’ll need the JDK.
3. How do I uninstall Java 8?
To uninstall Java 8, first identify the installation directory. Then, remove the directory and any environment variables related to it. If you used alternatives, revert the changes made by using sudo update-alternatives --remove.
sudo rm -rf /opt/java/jdk1.8.0_XXX # Replace with your actual directory # Remove JAVA_HOME and PATH entries from .bashrc or .zshrc 4. What if I have multiple Java versions installed?
Having multiple Java versions can lead to conflicts. Use the alternatives command (on Debian-based systems) to manage and switch between Java versions. Otherwise, carefully manage your JAVA_HOME and PATH environment variables, ensuring they point to the desired version for each session or application.
5. How do I resolve a “java command not found” error?
This error indicates that the java executable is not in your system’s PATH. Double-check your environment variables and ensure that $JAVA_HOME/bin is correctly added to the PATH. Also, verify that JAVA_HOME points to the correct Java installation directory.
6. Can I install Java 8 on a 64-bit or 32-bit Linux system?
Yes, but you need to download the correct version for your system architecture. A 64-bit version of Java 8 is needed for a 64-bit operating system and similarly for a 32-bit operating system. Using the incorrect architecture will prevent Java from working.
7. Why should I prefer Eclipse Temurin over Oracle JDK?
Eclipse Temurin offers several advantages: it’s open-source, freely available without licensing restrictions, and regularly updated. It’s also generally easier to install and manage, especially for developers new to Java.
8. What are the system requirements for Java 8 on Linux?
Java 8 generally requires a minimum of 128 MB of RAM, a 1 GHz processor, and sufficient disk space for the installation. The exact requirements may vary depending on the specific Linux distribution and the complexity of the Java applications you intend to run.
9. How do I run a specific Java program after installing Java 8?
After installing Java 8 and setting up your environment variables, you can run a Java program using the java command followed by the name of the compiled .class file or .jar file. For example:
java MyProgram java -jar MyApplication.jar 10. Can I use a package manager like apt or yum to install Java 8?
While some older Linux distributions might have Java 8 packages available through their package managers, these packages are often outdated or incomplete. It’s generally recommended to download the JDK or JRE directly from Oracle or Eclipse Temurin and install it manually to ensure you have the latest and most reliable version.
11. How do I set the default Java version on my system?
On Debian-based systems, use the alternatives command. Otherwise, the Java version used will be the version whose binaries appear first in your PATH variable. Modify your shell’s configuration file (.bashrc or .zshrc) to change this ordering.
12. Is Java 8 still secure to use in 2024?
While Java 8 received extended support from Oracle, it’s important to be aware that it no longer receives public updates for security vulnerabilities. Using more recent versions of Java like Java 11 or Java 17 is highly recommended for better security. If Java 8 is required, ensure you have adequate security measures in place and consider using a commercially supported version with extended support options.
By following these steps and understanding the nuances of Java 8 installation, you can successfully set up your Linux system to run your legacy applications and continue your Java development journey. Good luck!
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