![\"\"](\"https:\/\/www.hostinger.com\/tutorials\/wp-content\/uploads\/sites\/2\/2022\/11\/Linux-cheat-sheet-1024x283.png\")
<\/a><\/figure><\/div>\n\n\n\n<\/p>
Prerequisites for Installing Java on Ubuntu<\/h2>
Before you start installing Java on Ubuntu, ensure you meet the following prerequisites:<\/p>
- \n
- Familiarity with the command line<\/strong>. It’s crucial to have a foundational knowledge of Linux commands<\/a> and Ubuntu terminal navigation. This will facilitate the Java installation process and subsequent management tasks.<\/li>\n\n\n\n
- Access to an Ubuntu server<\/strong>. If you’re using a virtual private server (VPS)<\/a>, ensure you have access with sudo <\/strong>privileges to execute administrative commands within the server. For enhanced stability and extended support, we recommend opting for recent long-term support (LTS) versions of Linux distributions, such as Ubuntu 22.04 LTS<\/strong>.<\/li>\n\n\n\n
- Java code understanding<\/strong>. While not necessary for installation, having a basic knowledge of Java coding is beneficial for those looking to develop Java-based applications. As one of the most popular programming languages, Java offers extensive documentation and community support to enhance your programming skills.<\/li>\n<\/ul>
How to Install Java on Ubuntu<\/h2>
This section will explain how to install and configure Java for Ubuntu using a Hostinger VPS plan<\/a>.<\/p>
![\"\"](\"https:\/\/www.hostinger.com\/tutorials\/wp-content\/uploads\/sites\/2\/2023\/02\/VPS-hosting-banner-1024x300.png\")
<\/a><\/figure>1. Update the Package Index<\/h3>
For a smooth Java installation, ensure your Ubuntu system is up-to-date. Start by securely logging into your server using an SSH client like PuTTY<\/a> and entering your credentials to access the system.<\/p>
Refresh your system’s connection to the APT repository by updating the package indexes:<\/p>
sudo apt update\nsudo apt upgrade<\/pre>
The sudo apt update<\/strong> command contacts the package repository to retrieve the latest list of available packages and their versions without installing or upgrading any software.<\/p>
Following this, sudo apt upgrade <\/strong>installs the available updates, which may include security patches and improved versions of packages, ensuring your system’s security and compatibility.<\/p>
2. Install the Default JRE<\/h3>
If you’re primarily focused on running Java programs, you’ll only need to install the Java Runtime Environment (JRE) on Ubuntu. Here’s the command you should execute:<\/p>
sudo apt install default-jre<\/pre>
Facilitated by the APT package manager, this command installs the default JRE package. This default version is chosen for its stability and comprehensive support within the Ubuntu distribution.<\/p>
It includes the Java Virtual Machine (JVM), core classes, and supporting libraries required to run Java applications.<\/p>
3. Install a Specific Java (JDK) Version<\/h3>
For software development tasks, installing the Java Development Kit (JDK) on Ubuntu is essential. The JDK includes the JRE and key development tools like the Java compiler (javac<\/strong>) and debugger, which are necessary for building Java applications.<\/p>
Installing the Default JDK<\/strong><\/p>
The OpenJDK package is recommended for most development needs due to its ease of installation and open-source licensing. To install the default version of JDK, use:<\/p>
sudo apt install default-jdk<\/pre>
Installing Specific Versions of OpenJDK<\/strong><\/p>
You may need a specific Java version for compatibility purposes. For a particular OpenJDK installation on Ubuntu, first, search for the available versions with the following command:<\/p>
apt search openjdk<\/pre>
Then, install your desired OpenJDK version, such as OpenJDK 11, using:<\/p>
sudo apt install openjdk-11-jdk<\/pre>
Installing Oracle JDK<\/strong><\/p>
If your preference leans towards Oracle Java on Ubuntu due to its specific features or application compatibility, be aware that it requires manual installation, as Oracle JDK cannot be installed through package managers.<\/p>
Oracle’s JDK 21 is the latest long-term support release of the Java SE Platform as of this writing. To install Oracle JDK, follow these steps:<\/p>
- \n
- Visit the Oracle download page<\/a> to find the JDK version suitable for Ubuntu (x64 Compressed Archive<\/strong>). You can also obtain the official JDK Debian package here.<\/li>\n<\/ol>
![\"Choosing](\"\/tutorials\/wp-content\/uploads\/sites\/2\/2024\/04\/oracle-java-downloads-page-x64-compressed-archive-highlighted-1024x579.png\")
<\/a><\/figure><\/div>- \n
- After accepting the license agreement, download the .tar.gz<\/strong> file for your desired version.<\/li>\n\n\n\n
- Use an FTP client like FileZilla<\/a> or the scp command<\/a> to upload Oracle’s JDK to your Ubuntu server. Choose a directory like \/tmp<\/strong> or \/opt<\/strong> for the upload. If opting for scp<\/strong>, use this command, replacing username <\/strong>and server_ip <\/strong>with your actual credentials:<\/li>\n<\/ol>
scp \/path\/to\/jdk-archive.tar.gz username@server_ip:\/tmp<\/pre>
- \n
- Navigate to the directory where you uploaded the file and extract it using:<\/li>\n<\/ol>
tar -xzf <filename>.tar.gz<\/pre>
- \n
- Move the extracted folder to a more permanent location, such as \/usr\/lib\/jvm\/<\/strong>, with:<\/li>\n<\/ol>
sudo mv <extracted-folder-name> \/usr\/lib\/jvm\/oracle-jdk-<version><\/pre>
4. Verify the Installation<\/h3>
After installing Java, it’s crucial to confirm that the installation was successful and that your system is using the correct version.<\/p>
To check the installed version of the JRE, run the following command:<\/p>
java -version<\/pre>
To verify the Java Development Kit version, including the compiler, enter:<\/p>
javac -version<\/pre>
Output and Interpretation<\/strong><\/p>
The output should display the version number and build information. For example:<\/p>
java version \"21.0.2\" 2024-01-15\nJava(TM) SE Runtime Environment (build 21.0.2+10-LTS)\nJava HotSpot(TM) 64-Bit Server VM (build 21.0.2+10-LTS, mixed mode)<\/pre>
This confirms Java 21.0.2<\/strong> is the installed Java version, with mixed mode<\/strong> indicating the JVM’s ability to run both just-in-time compiled and interpreted code, optimizing performance.<\/p>
Configuring the Default Java Version<\/strong><\/p>
Ubuntu allows for multiple Java installations. If you have several installed, set the default version with the update-alternatives <\/strong>command:<\/p>
sudo update-alternatives --config java<\/pre>
This command lists all installed Java versions, allowing you to perform the Ubuntu Java version switch by entering its selection number.<\/p>
- Move the extracted folder to a more permanent location, such as \/usr\/lib\/jvm\/<\/strong>, with:<\/li>\n<\/ol>
- Use an FTP client like FileZilla<\/a> or the scp command<\/a> to upload Oracle’s JDK to your Ubuntu server. Choose a directory like \/tmp<\/strong> or \/opt<\/strong> for the upload. If opting for scp<\/strong>, use this command, replacing username <\/strong>and server_ip <\/strong>with your actual credentials:<\/li>\n<\/ol>
- After accepting the license agreement, download the .tar.gz<\/strong> file for your desired version.<\/li>\n\n\n\n
- Access to an Ubuntu server<\/strong>. If you’re using a virtual private server (VPS)<\/a>, ensure you have access with sudo <\/strong>privileges to execute administrative commands within the server. For enhanced stability and extended support, we recommend opting for recent long-term support (LTS) versions of Linux distributions, such as Ubuntu 22.04 LTS<\/strong>.<\/li>\n\n\n\n