Openjdk set java home

How to Set JAVA_HOME Variable in Ubuntu Linux Correctly

If you are running Java programs on Ubuntu using Eclipse, Maven or Netbeans etc, you’ll need to set JAVA_HOME to your path. Otherwise, your system will complain that “java_home environment variable is not set”.

In this beginner’s tutorial, I’ll show the steps to correctly set Java Home variable on Ubuntu. The steps should be valid for most other Linux distributions as well.

The process consists of these steps:

• Making sure Java Development Kit (JDK) is installed.
• Finding the correct location of JDK executable.
• Setting the JAVA_HOME variable and making the change permanent.

Step 1: Check if JDK is installed

The simplest way to check if Java Development Kit (JDK) is installed on your Linux system is by running this command:

The above command checks the version of Java compiler. If it is installed, it will show the Java version.

If the command shows an error like javac command not found, you’ll have to install JDK.

If Java Compiler is not installed on your system, install Java Development Kit using this command:

sudo apt install default-jdk

This will install the default Java version in your current Ubuntu version. If you need some other specific Java version, you’ll have to specify it while installing Java on Ubuntu.

Once you have made sure that Java Compiler is present on your system, it’s time to find its location.

Step 2: Get the location of JDK executable (Java Compiler)

The executable is usually located in the /usr/lib/jvm directory. I won’t left you on your own for a guessing game. Instead, let’s find out the path of the Java executable.

Use the which command to get the location of Java Compiler executable:

The problem here is that the location it gives is actually a symbolic link. You’ll have to follow it a couple of times:

And when you find a path like /usr/lib/jvm/java-11-openjdk-amd64/bin/javac, you remove the /bin/javac from it to get something like /usr/lib/jvm/java-11-openjdk-amd64

An easier method is to follow the symbolic link and get to the actual executable file directly using this command:

readlink -f `which javac` | sed "s:/bin/javac::"

The readlink command follows a symbolic link. I have used ` around which java. This is called command substitution and it replaces the command with its output. Sed is then used to replace /bin/javac by nothing and thus removing it altogether.

In my example, the location of the executable file is /usr/lib/jvm/java-11-openjdk-amd64. It could be different for you. Copy the correct path you got from the above command in your system. You know, you can copy paste in the Ubuntu terminal.

Step 3: Setting JAVA_HOME variable

Now that you have got the location, use it to set the JAVA_HOME environment variable:

export JAVA_HOME=/usr/lib/jvm/java-11-openjdk-amd64/bin/java

Check the value of JAVA_HOME directory:

Try to run your program or project in the SAME TERMINAL and see if it works.

This is not over yet. The JAVA_HOME variable you just declared is temporary. If you close the terminal or start a new session, it will be empty again.

To set JAVA_HOME variable ‘permanently’, you should add it to the bashrc file in your home directory.

You can use the Nano editor for editing files in the Linux terminal. If you do not want that and take a simple copy-paste approach, use the following commands:

Back up your bashrc file (in case you mess it, you can get it back):

Next, use the echo command to append the export command you used at the beginning of this section. Change the command below to use the correct path as displayed by your system in.

echo "export JAVA_HOME=/usr/lib/jvm/java-11-openjdk-amd64" >> ~/.bashrc

Verify that it has been correctly added to the end of the file:

The above tail command will show the last 3 lines of the specified file.

Here’s the entire output of the above three commands.

Now, even if you exit the session or restart the system, the JAVA_HOME variable will still be set to the value you specified. That’s what you want, right?

Do note that if you change the default Java version in the future, you’ll have to change the value of JAVA_HOME and point it to the correct executable path.

I hope this tutorial not only helped you to set Java Home, it also taught you how you are doing it.

If you are still facing issues or have any questions or suggestions, please let me know in the comments.

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How to Set JAVA_HOME Path in Ubuntu 20.04 and Ubuntu 22.04

Many Java-based programs require the Java Runtime Environment (JRE) to run smoothly regardless of the operating system. For development, most IDEs like Eclipse and NetBeans require the Java Development Kit (JDK) on your computer. Whether you’re a newbie who wants to learn how to develop or an application you have installed requires a Java installation on your system, we’ve got you covered. Setting up the JAVA_HOME path is quite simple.

In this tutorial, we will learn how to install the JDK on Ubuntu 20.04 and Ubuntu 22.04 and set up the Java_HOME path. Let’s start with the installation of the JDK.

Install OpenJDK on Ubuntu

Note: Make sure that you have updated the Advanced Package Tool (APT) before you move forward to install OpenJDK.

Press Ctrl + Alt + T to open the terminal and enter the following command mentioned in the box. You can either install OpenJDK 8 or the newer versions OpenJDK 11 to OpenJDK 18. Not all versions are available on any Ubuntu version, you can check for available versions with the command:

Install OpenJDK 8

sudo apt install openjdk-8-jdk

Install OpenJDK 11

sudo apt install openjdk-11-jdk

Install OpenJDK 14

sudo apt install openjdk-14-jdk

Install OpenJDK 16

sudo apt install openjdk-16-jdk

Install OpenJDK 17

sudo apt install openjdk-17-jdk

Install OpenJDK 18

sudo apt install openjdk-18-jdk

You will be prompted to enter your sudo password to continue with the installation.

Once you’ve entered that, wait for the system to finish the installation and then move on to step 2.

Set JAVA_HOME Path

All you have to do now is to set the “JAVA_HOME” and “PATH” environment variables and then you are done. Enter the following commands to set your environment variables. Make sure that your environment variables point to a valid installation of JDK on your machine. For Ubuntu 18.04, the path is /usr/lib/jvm/java-8-openjdk-amd64/

export JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64

To check whether your JAVA_HOME path has been successfully saved, enter the following command to check.

The value stored in the JAVA_HOME variable will be displayed on the terminal as you can see in the screenshot

Add JAVA bin directory to the PATH variable

Like we have added JAVA_HOME path, we will now update the PATH variable as well. To do that, enter the following command on the terminal.

export PATH=$PATH:$JAVA_HOME/bin

This will append the java bin directory to the existing PATH variable. You can also check the PATH variable by entering the following command

Test JAVA setup

You have successfully installed OpenJDK on your machine. You can verify your installation by entering the following command on your terminal.

Through this simple tutorial, you have now configured the JAVA_HOME variable in your operating system. You can now easily run java based applications as well as development environments on your machine.

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How to setup the JAVA_HOME path in Debian 11

Java is a very popular programming language that is used in desktop software development, mobile applications, business applications, and so on. It requires the installation of the Java Runtime Environment (JRE) and Java Development Kit (JDK) in order to develop and run Java applications. After installation of JRE and JDK, you also need to set up JAVA_HOME in order for many java based applications to work properly. JAVA_HOME is basically an OS environment variable that points to the directory where the JDK or JRE is installed on your system. It needs to be configured in all OSs with Java installed such as Linux, Windows, and macOS.

In this article, we will learn how to install Java JDK on Debian OS and then set up the JAVA_HOME and PATH variables.

We have run the commands and procedure mentioned in this article on a Debian 11 system. The same procedure can be followed in other Linux distributions and older versions of Debian as well.

Let’s start by installing JDK first.

Install OpenJDK on Debian

First, launch the Terminal in your OS. Go to the Activities tab in the top left corner of your desktop. Then search for the Terminal application by typing the relevant keyword in the search bar. From the results, click on the Terminal icon to open.

Now in the Terminal, run this command as sudo to install Open JDK.

$ sudo apt install openjdk-17-jdk

When prompted for the password, enter the sudo password.

The system might ask for confirmation by providing the Y/n option. Hit y and then Enter to confirm, after which the installation of Open JDK will be started on your system.

Set JAVA_HOME Path

Find out the installation path of OpenJDK on your system. Usually, it is /usr/lib/jvm/java-17-openjdk-amd64/. To set the JAVA_HOME environment path, enter the following command in Terminal:

$ export JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64

Now you have set the JAVA_HOME path, you can verify it by running the following command in Terminal:

In the output, you will see the value stored in the JAVA_HOME variable as displayed in the following screenshot.

Add the JAVA bin directory to the PATH variable

Similar to the JAVA_HOME path, we will now add the $PATH variable as well. $PATH variable points to the bin directory under the JDK installation directory. As the JDK directory location has already been set up using the JAVA_HOME variable, now we can just use the JAVA_HOME attribute to set up the bin directory location.

Enter this command in Terminal to add the Java bin directory to the PATH variable:

$ export PATH=$PATH:$JAVA_HOME/bin

Java bin directory will be appended to the existing PATH variable. To verify it, run the following command in Terminal:

Test JAVA setup

Now we have installed OpenJDK and set up the JAVA_HOME and PATH variables, now its time to verify the installation. In the Terminal, run the following command to do so:

So there you have it! In this article, you have learned how to set up the JAVA_HOME variable in your Debian OS. Now you can easily develop and run JAVA applications on your system.

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Vitux.com aims to become a Linux compendium with lots of unique and up to date tutorials.

Latest Tutorials

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