Java Development Kit (JDK) and Eclipse Integrated Development Environment (IDE) are two essential tools for Java developers. In this article, we will guide you through the process of installing JDK and Eclipse IDE, as well as how to manage multiple versions of Java on a single system.
Installing JDK
Step 1: Download the JDK First, you need to download the JDK from the Oracle website. Go to the Oracle website and download the appropriate JDK version for your operating system. Choose the version that matches your system’s architecture (32-bit or 64-bit).
Step 2: Install the JDK After downloading the JDK, run the installer and follow the installation wizard. Choose the installation directory and click on “Next” to proceed. Accept the license agreement and click on “Next”. The JDK will be installed on your system. You can watch this youtube video if you need help in installing jdk https://youtu.be/ogWKP9Lm-Qo
Step 3: Set the JAVA_HOME environment variable After installing the JDK, you need to set the JAVA_HOME environment variable. This is necessary to make sure that your system knows where to find the JDK installation directory.
On Windows:
- Right-click on “My Computer” and choose “Properties”.
- Click on “Advanced system settings”.
- Click on “Environment Variables”.
- Click on “New” under “System Variables”.
- Enter “JAVA_HOME” as the variable name.
- Enter the path of the JDK installation directory as the variable value.
On Linux/Mac:
- Open the terminal.
- Type the following command:
sudo nano /etc/environment - Add the following line at the end:
JAVA_HOME="/usr/lib/jvm/java-11-openjdk-amd64"(replace the path with your JDK installation path) - Save and exit the file.
Installing Eclipse IDE
Step 1: Download Eclipse Go to the Eclipse website and download the appropriate Eclipse version for your operating system. Choose the version that matches your system’s architecture (32-bit or 64-bit).
Step 2: Install Eclipse After downloading Eclipse, extract the downloaded file to your preferred directory. You can run Eclipse from the extracted directory.
Managing Multiple Versions of Java
Sometimes you may need to use different versions of Java for different projects. Here’s how to manage multiple versions of Java on a single system.
Step 1: Install Multiple Versions of Java To install multiple versions of Java on your system, you can use your system’s package manager. For example, on Ubuntu, you can install the OpenJDK package for a specific version using the following command:
sudo apt-get install openjdk-11-jdk
Step 2: Set up update-alternatives After installing multiple versions of Java, you need to set up update-alternatives to manage which version of Java should be used by default. The update-alternatives tool allows you to choose which version of a program should be used when you run a command.
To set up update-alternatives, run the following command:
sudo update-alternatives --install /usr/bin/java java /usr/lib/jvm/java-11-openjdk-amd64/bin/java 1
This command adds a new alternative for the java command that points to the JDK installation directory of version 11. You can repeat this command for each installed version of Java.
Step 3: Configure Eclipse to use the required version of Java To configure Eclipse to use a specific version of Java, follow these steps:
- Open Eclipse and go to “Window” -> “Preferences”.
- Expand the “Java” menu and click on “Installed JREs”.
- Click on “Add” to add a new JRE.
- Choose “Standard VM” and click on “Next”.
- Enter the JRE name and the JRE home directory. The JRE home directory should point to the installation directory of the required version of Java.
- Click on “Finish” to add the new JRE.
- Now, you need to set the default JRE for the workspace. Go to “Window” -> “Preferences” and expand the “Java” menu.
- Click on “Installed JREs” and select the newly added JRE.
- Click on “Apply and Close” to save the changes.
You can repeat these steps for each version of Java that you have installed on your system.
Step 4: Switch between Java versions using update-alternatives To switch between different versions of Java, you can use the update-alternatives tool. Use the following command to switch to a specific version of Java:
sudo update-alternatives --config java
This command will display a list of all the installed versions of Java. Choose the version that you want to use and press “Enter”. The selected version will be used by default for all Java applications.
Conclusion
In this article, we have explained how to install JDK and Eclipse IDE, as well as how to manage multiple versions of Java on a single system. By following these steps, you can easily switch between different versions of Java and ensure that your projects run on the desired version of Java. The use of update-alternatives tool can be particularly useful in managing and installing multiple versions of Java.