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G Sudarshan
G Sudarshan

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Installing Java on Ubuntu 20.04 [ Easy Way ]

In this guide, we will describe how to install Java on Ubuntu 20.04.

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Installing OpenJDK 11

Open Terminal, As always first check for updates

sudo apt-get update
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Then type following command in terminal

sudo apt install openjdk-11-jdk
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when asked for [ Y/n ], Type Y

Once the installation is complete, you can verify it by checking the Java version:

java -version
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The output should look something like this:

openjdk version "11.0.7" 2020-04-14
OpenJDK Runtime Environment (build 11.0.7+10-post-Ubuntu-3ubuntu1)
OpenJDK 64-Bit Server VM (build 11.0.7+10-post-Ubuntu-3ubuntu1, mixed mode, sharing)
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JAVA_HOME Environment Variable

The JAVA_HOME environment variable is used by some Java applications to determine the Java installation location.

To set the JAVA_HOME variable, first find the Java installation path with update-alternatives:

sudo update-alternatives --config java
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In this example, the installation paths are as follows:

  • OpenJDK 11 is located at /usr/lib/jvm/java-11-openjdk-amd64/bin/java

Once you found the path of your preferred Java installation, open the /etc/environment file:

sudo nano /etc/environment
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Assuming you want to set JAVA_HOME to point to OpenJDK 11, add the following line, at the end of the file:

/etc/environment

JAVA_HOME="/usr/lib/jvm/java-11-openjdk-amd64"
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For changes to take effect on your current shell you can either log out and log in or run the following [source](https://linuxize.com/post/bash-source-command/) command:

source /etc/environment
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Verify that the JAVA_HOME environment variable was correctly set:

echo $JAVA_HOME
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You should see the path to the Java installation:

That’s it! At this point, you have successfully installed Java on your Ubuntu system!

Now for complete assurance

Open any text editor type following following code

class Simple{  
        public static void main(String args[]){  
         System.out.println("Hello Java");  
        }  
    }
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save this code as Simple.java

cd to the folder where the program is saved.

then compile using following command in terminal. ( remember S is capital in Simple )

javac Simple.java
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and then run using following command

java Simple
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If you are able to see this output ..... then your java is successfully installed on Ubuntu!

Hello Java
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Uninstalling Java

You can uninstall Java like any other package installed with apt .

For example, to uninstall the default-jdk package enter:

sudo apt remove openjdk-11-jdk
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Conclusion

OpenJDK 11 and OpenJDK 8 are available in the default Ubuntu 20.04 repositories and can be installed using the apt package manager.

GitHub: https://github.com/G-Sudarshan

LinkedIn: https://www.linkedin.com/in/g-sudarshan

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Discussion (2)

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clavinjune profile image
Clavin June

I recommend using sdkman to install Java, it helps you maintaining multiple java version

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gsudarshan profile image
G Sudarshan Author

Awesome alternative✔️👍