Wondering about how to install Java on Ubuntu? Installing Java is certainly one of the first few things to do after installing Ubuntu and it is very easy to do so.

Many people have aversion to Java. But there are high chances that for one reason or other, you might have to install Java, no matter how much you dislike it. In this quick post, we shall see how to install Java in Ubuntu, Linux Mint and other Debian and Ubuntu based distributions.

You can get Java on Ubuntu via multiple packages. There is JRE, OpenJDK and Oracle JDK. But what is the difference between these packages and which one should you install? Let me explain that in the next section.

JRE vs OpenJDK vs Oracle JDK
Before we go on seeing the process to install Java, let’s quickly understand the difference between JRE, OpenJDK and Oracle JDK.

JRE (Java Runtime Environment) is what you would need normally to run a Java-based application. This is all you need if you are not a programmer.
JDK (Java Development Kit) is what you need to if you have to do some do some programming or develop software related to Java.
OpenJDK is Open Source implementation of Java Development Kit while Oracle JDK is the official Oracle version of Java Development Kit. While OpenJDK is sufficient for most of the cases, some programs such Android Studio suggests using Oracle JDK to avoid UI/performance issue.
Now that you know the difference between JRE, JDK, OpenJDK and Oracle JDK, you should make a decision to install one of these packages.

Once you do that, it’s time to see how to install these packages and get Java on your Ubuntu Linux.

Check if Java is already installed in Ubuntu
Before you see how to install Java, you should verify if Java is already installed. This is also helpful in knowing which version of Java is installed on your system.

Open a terminal and use the following command:

java -version
If you have Java installed, you should see an output like this:

openjdk 10.0.2 2018-07-17
OpenJDK Runtime Environment (build 10.0.2+13-Ubuntu-1ubuntu0.18.04.4)
OpenJDK 64-Bit Server VM (build 10.0.2+13-Ubuntu-1ubuntu0.18.04.4, mixed mode)
As you can see in the above output, the system has Java 10 installed via OpenJDK.

If you don’t have Java installed on your system, you’ll see an output like this:

The program ‘java’ can be found in the following packages:
* default-jre
* gcj-4.6-jre-headless
* openjdk-6-jre-headless
* gcj-4.5-jre-headless
* openjdk-7-jre-headless
Try: sudo apt-get install
Basically Ubuntu is giving you hint about the various packages you can install to get Java.

Install Java in Ubuntu and Linux Mint
Once we have see the difference between various types of ‘Java’, let’s see how to install them.

Install JRE in Ubuntu and Linux Mint
Open terminal and use the following command to install JRE:

sudo apt install default-jre
This will install the latest JRE available from Ubuntu. But if you want to install a specific version, you can use openjdk-8-jre, openjdk-7-jre/openjdk-6-jre instead of default-jre in the above command.

Install OpenJDK in Ubuntu and Linux Mint
In a terminal, use the following command to install OpenJDK Java Development Kit:

sudo apt install default-jdk
If you are specifically looking to install Java 8, Java 7 or Java 6 etc, you can use openjdk-8-jdk, openjdk-7-jdk/openjdk-6-jdk.

Install Oracle JDK in Ubuntu and Linux Mint
Use the following commands to install Oracle JDK in Ubuntu and Linux Mint. Just a heads up, it will download plenty of files. So make sure you have good internet speed:

sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
If you want to install Java 10 and set it as default, use the following command:

sudo apt install oracle-java10-installer
sudo apt install oracle-java10-set-default
If you want to install Java 8 and set it as default, use the following command:

sudo apt install oracle-java8-installer
sudo apt install oracle-java8-set-default

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