How to Check Java Version in Linux
In the world of programming, Java remains a popular choice for developing a wide range of applications. Whether you are a developer or a system administrator, it is crucial to know the version of Java installed on your Linux system. This information helps in identifying compatibility issues, managing dependencies, and ensuring smooth operation of Java-based applications. In this article, we will discuss various methods to check the Java version in Linux.
Using the `java -version` Command
The simplest and most common method to check the Java version in Linux is by using the `java -version` command. This command displays the version of Java installed on your system, along with additional information such as the implementation vendor and the Java Virtual Machine (JVM) version.
To use this method, open your terminal and type the following command:
“`
java -version
“`
The output will look something like this:
“`
java version “1.8.0_251”
Java(TM) SE Runtime Environment (build 1.8.0_251-b08)
Java HotSpot(TM) 64-Bit Server VM (build 25.25-b02, mixed mode)
“`
This output indicates that Java 1.8.0_251 is installed on your system.
Using the `javac -version` Command
Another method to check the Java version is by using the `javac -version` command. This command specifically checks the version of the Java compiler, which is a part of the Java Development Kit (JDK). It provides similar information to the `java -version` command.
To use this method, open your terminal and type the following command:
“`
javac -version
“`
The output will display the version of the Java compiler installed on your system. For example:
“`
javac 1.8.0_251
“`
This output indicates that the Java compiler version is 1.8.0_251.
Using the `java -version` Command with Alternative Shells
If you are using an alternative shell like Bash, Zsh, or Ksh, you can still use the `java -version` command to check the Java version. The command works the same way across different shells.
To check the Java version using an alternative shell, follow these steps:
1. Open your terminal.
2. Type the following command:
“`
java -version
“`
3. Press Enter, and you will see the Java version information.
Using the `update-alternatives` Command
The `update-alternatives` command is a powerful tool in Linux that allows you to manage multiple versions of the same program. It can be used to check the Java version installed on your system.
To use this method, open your terminal and type the following command:
“`
update-alternatives –config java
“`
This command will display a list of available Java versions installed on your system. You can select the desired version by entering the corresponding number and pressing Enter.
Conclusion
Checking the Java version in Linux is essential for managing Java-based applications and ensuring compatibility. By using the `java -version` and `javac -version` commands, you can quickly determine the Java version installed on your system. Additionally, the `update-alternatives` command provides an alternative way to manage multiple Java versions. With these methods, you can easily maintain and troubleshoot Java applications on your Linux system.
