Installing Java on Linux follows the download-extract-configure pattern. We will begin by downloading Oracle Java from Oracle’s website, extracting the download in the appropriate folder, and finally informing Ubuntu about the newly installed version of Java.
Step 1: Verify that you do not already have the correct version of Java installed.
Open your console window and enter the following command:
If you get the following result, you already have Java 7 update 21 installed and can ignore the rest of the steps:
java version 1.7.0_21 Java(TM) SE Runtime Environment (build 1.7.0_21-b11) Java HotSpot(TM) Client VM (build 23.21-b01, mixed mode)
Step 2: Download Oracle Java.
New release of Java are featured on the main Java download page.
If Java 7 update 21 is no longer featured, you can find the download by following the Previous Releases link found on the main download page.
Open the Java download page in your browser and download jdk-7u21-linux-i586.bin.
Make a note of the folder to which you downloaded the file. For further reference in this blog, I will call this folder the “downloads folder”.
Step 3: Create the installation folder.
usr/lib/jvm is the default installation location of the Java JDK. Enter the following command in your console to create this folder, if it does not already exist:
sudo mkdir -p /usr/lib/jvm
–p option ensures that all folders in the
mkdir path are created.
Step 4: Navigate to the “downloads folder”.
If you downloaded the file to your Home folder, you can use the following command:
"~/" with the path to the “downloads folder”.
Step 5: Move the downloaded archive to the installation folder.
sudo mv jdk-7u21-linux-i586.tar.gz /usr/lib/jvm
Step 6: Navigate to the “installation folder”.
Step 7: Unpack the tarball archives.
sudo tar zxvf jdk-7u21-linux-i586.tar.gz
If you want to conserve space you may delete the tarball archives.
sudo rm jdk-7u21-linux-i586.tar.gz
Step 8: Display the contents of the installation folder.
Make a note of the newly created folder names.
Step 9: Inform Ubuntu where your Java installation is located.
sudo update-alternatives --install "/usr/bin/javac" "javac" "/usr/lib/jvm/jdk1.7.0_21/bin/javac" 1 sudo update-alternatives --install "/usr/bin/java" "java" "/usr/lib/jvm/jdk1.7.0_21/bin/java" 1
Step 10: Inform Ubuntu that this is your default Java installation.
sudo update-alternatives --set "javac" "/usr/lib/jvm/jdk1.7.0_21/bin/javac" sudo update-alternatives --set "java" "/usr/lib/jvm/jdk1.7.0_21/bin/java"
Step 11: Update your system-wide PATH.
/etc/profile file using:
sudo nano /etc/profile
Add the following entries to the bottom of your
JAVA_HOME=/usr/lib/jvm/jdk1.7.0_21 PATH=$PATH:$JAVA_HOME/bin export JAVA_HOME export PATH
/etc/profile file using
CTRL + X.
Step 12: Reload your system-wide PATH.
Step 13: Test your new installation.
java version 1.7.0_21 Java(TM) SE Runtime Environment (build 1.7.0_21-b12) Java HotSpot(TM) Client VM (build 23.21-b01, mixed mode)