How To Find and Verify Installed Java Runtime Version?

Java Runtime Environment is used to run Java applications. Java Runtime Environment is called JRE. There are different versions of JRE most recent major versions are 6,7,8. Some of the applications generally require a different version because of comp ability problems. In this tutorial, we will look at how to get JRE or Java versions from various operating systems. If you want to learn JRE and differences with JDK please read the following tutorial.

Java JDK vs JRE What Are Differences and Similarities?

Java or JRE Version Numbers

Java uses a bit different version numbers. All java versions first numbers is 1  actual major version numbers change according to release which is current 8 . Example Java version number is like below.

1.8.0_99

Determine Java Version in Windows From Command Line

We have different methods to determine Java or JRE version in windows. The first way is running java command in command like with version information. We will also provide -version option like below.

> java -version
Determine JAVA Version in Windows
Determine JAVA Version in Windows

We can see that cırrent JRE or Java version is 1.8.0_144 . Here we can call 8 as a major version number.

Determine Java Version in Windows From GUI

We can use the Java menu which resides in the Control Panel.

Determine JAVA Version in Windows From GUI
Determine Java Version in Windows From GUI

And then In the General tab click to About button. This will open a new window that will provide information about the current Java or JRE version.

Determine JAVA Version in Windows From GUI
Determine Java Version in Windows From GUI

We can see and get the following information.

  • `Version 8` specifies the main version of Java which is 8 in this example.
  • `Update 144` specifies the minor version which numbered as 144.

Determine Java Version Linux (CentOS, RedHat, Fedora, Ubuntu, Debian, Kali, Mint)

We will use java command from the command line to get information about Java or JRE installation of Linux distributions.

$ java -version
Determine Java Version Linux (CentOS, RedHat, Fedora, Ubuntu, Debian, Kali, Mint)
Determine Java Version Linux (CentOS, RedHat, Fedora, Ubuntu, Debian, Kali, Mint)

We can see that a lot of information about Java and the platform is provided.

  • `openjdk version “1.8.0_131″` is the current version of Java. We can see that the Java implementation is OpenJDK which is an open version of Java for Linux distributions.
  • `ubuntu` is the operating system where Java is created.
  • `OpenJDK 64-Bit Server VM` specifies the Java CPU architecture which is 64 bit.

Determine Java Version Online

We can also use the currently installed Java version from the web. We will navigate to the following URL which is provided by Oracle Java. We will see a screen like below. First, we will click on the Agree and Continue button.

https://www.java.com/en/download/installed.jsp

Determine Java Version Online
Determine Java Version Online

For security reasons, current popular browsers have disabled the Java or JRE by default. So Google Chrome, Mozilla Firefox, etc. will show a warning like Java is disabled or not installed. If Java is enabled for browser we will see the current version of Java without a problem.

Java Disabled or Not Installed Warning

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