What is my java jdk version

How to know the jdk version on my machine?

First uninstall all the versions of Java, install Jdk 8. Open new command prompt and type java -version.

If your JDK is on your path you should be able to tell by just running ‘javac -version’. From the error you described it sounds like you’re on Windows, so if the first command fails try executing (with the quotes) the following: «%JAVA_HOME%\bin\javac -version»

@AlexBroadwin your method worked for me. But i’ve installed 8th version and in cmd «1.8.0_221» is coming. What does that mean?

4 Answers 4

you might need to add path in environment variables which you can find in Control Panel open the Jdk where you installed and add until /bin in the path in environment variables.

Add until /bin in path variable in System Variables which is residing in Environment Variables.

Then do java -version which might show up.

If still problem persists, try restarting your pc and see.

Your method worked for me. But i’ve installed jdk version 8 and in cmd java version «1.8.0_221» is coming. What does that mean?

you are good, you have installed Java 8 and the _221 is just the update release(They keep on adding some features or there will be minor updates), for more info you can refer by clicking here oracle.com/technetwork/java/javase/…

-version is useless: C:\Windows\system32>java -version java version «1.8.0_281» Java(TM) SE Runtime Environment (build 1.8.0_281-b09) Java HotSpot(TM) 64-Bit Server VM (build 25.281-b09, mixed mode)

You need to update your Windows path to include your %JAVA_HOME%\bin directory. %JAVA_HOME% is the directory that you installed Java into and is also an environment variable that you need to configure for command line execution of your applications. You can edit both of these in the Windows control panel and you should restart.

When you run java -version you will see the internal version number. This is explained here: https://en.wikipedia.org/wiki/Java_version_history.

Basically, you can ignore the 1. when reading version number. The _xxx is a reference to the most recent patch or build release.

java version vs jdk versions could be different ? Seems useless or confusing at best ! JDK, JSE, it’s all a bit bloody mess

On Windows 10, this required mapping the environment variable for JAVA_HOME to the JDK installation directory. Use these steps:

1. Run the installer for the JDK. (available for windows here: https://www.oracle.com/java/technologies/downloads/#jdk17-windows)
2. windows key -> Environment Variables , select the only result
3. In the System Properties window that opened, select Environment Variables
4. Select new button under the User variables section
5. Variable name: JAVA_HOME , Variable Value:
6. ok all open menus
7. Close any open cmd prompt windows
8. open a new cmd window and type echo %JAVA_HOME% It should print the installation path for the JDK.

To get your jdk location in Windows, run this at a command prompt:

This lists any and all locations of java.exe, including from your JAVA_HOME. For example, the 3rd line here reflects my JAVA_HOME location, where I’m pointing to JDK 8:

C:\Users\me> where java C:\Program Files\Common Files\Oracle\Java\javapath\java.exe C:\Program Files (x86)\Common Files\Oracle\Java\javapath\java.exe C:\Program Files\Java\jdk1.8.0_202\bin\java.exe 

Note for comparison that java -version does not reflect my JAVA_HOME location and in fact shows java version 11 instead of 8:

C:\Users\me> java -version java version "11.0.15" 2022-04-19 LTS Java(TM) SE Runtime Environment 18.9 (build 11.0.15+8-LTS-149) Java HotSpot(TM) 64-Bit Server VM 18.9 (build 11.0.15+8-LTS-149, mixed mode) 

This is confusing because my Java compiles (e.g., via mvn) use JDK 8 since that’s what my JAVA_HOME is pointing to. (I’m not even sure where the version 11 it found came from; possibly from when I installed maven.)

Determining the difference between the JRE and JDK you’re running has never been straightforward. Seems like java -version used to be a way to do this, but no longer.

Adding to the complexity, you can also supposedly get your Java version info from Control Panel > Programs > Java > About. For me, that shows Version 8. That’s despite java -version showing version 11.0.15. And it doesn’t change even if I point my JAVA_HOME to JDK 11.

Note that this answer is also helpful. In my case, that helped me determine that I have java.exe and javac.exe at C:\Program Files (x86)\Common Files\Oracle\Java\javapath and C:\Program Files\Common Files\Oracle\Java\javapath . Depending on which one I have listed first in my Path variable, I get different results when i run java -version or java —version . The former seems to work when Java 8 is listed first; the latter when Java 11 is first.

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Check Your Java JDK Version: A Step-by-Step Guide for Windows, Mac, and Linux

Learn how to check your Java Development Kit (JDK) version on Windows, Mac, and Linux using command line. Follow our step-by-step guide and stay up-to-date with the latest Java JDK version.

• Introduction
• Checking JDK Version Using Command Line
• How to switch between the multiple Java versions(JDK) in windows 10
• Uninstalling All Versions of Java Before Installing JDK 8
• Switching Between Multiple JDK Versions on Windows
• Understanding Java SE 8 and Java SE 19
• Additional Information
• Best Practices for Java Programming
• Troubleshooting Java-Related Issues
• Improving Java Performance
• Other quick code examples for checking Java JDK versions
• Conclusion
• How to check Java JDK version in CMD?
• How do you check Java JDK is installed or not?
• How do I know if I have Java 8 or 11 in CMD?
• Is JDK 1.8 and JDK 8 are same?

Java Development Kit (JDK) is a crucial tool for developers working with Java. It contains all the necessary components to develop and run Java-based applications. Knowing the version of JDK installed on your computer is important for compatibility and security reasons. In this article, we will discuss how to check JDK version on Windows, Mac, and Linux through command line and other methods.

Introduction

As mentioned above, knowing the version of JDK installed on your computer is important for compatibility and security reasons. For instance, if you are working on a project that requires a specific version of JDK, you need to ensure that the correct version is installed on your computer. Additionally, updating your JDK to the latest version can improve security and performance.

Checking JDK Version Using Command Line

The most straightforward way to check the version of JDK installed on your computer is through the command line. Here are the steps for checking JDK version on Windows, Mac, and Linux:

1. Open the command prompt or terminal on your computer.
2. Type the following command to check the JDK version:

This command displays the version of the Java Compiler, which is included in the JDK.

This command displays the version of the Java Runtime Environment (JRE), which is also included in the JDK.

1. If you are working with IBM products like WebSphere and Information Server, you can determine the current JDK/SDK by using the following command:

How to switch between the multiple Java versions(JDK) in windows 10

In this Video i am going to show how to switch or manage the multiple Java versions of jdk Duration: 2:19

Uninstalling All Versions of Java Before Installing JDK 8

Before installing JDK 8, it is recommended to uninstall all other versions of Java to avoid compatibility issues. Here’s how to uninstall Java on Windows:

1. Open the Control Panel on your computer.
2. Click on Programs and Features.
3. Select the Java version you want to uninstall and click Uninstall.
4. Repeat the process for all other versions of Java.

After uninstalling all other versions of Java, you can install JDK 8. To check the JDK version after installation, use the following command:

Switching Between Multiple JDK Versions on Windows

If you have multiple versions of JDK installed on your Windows computer, you may need to switch between them depending on the project you are working on. Here are two methods for switching between multiple JDK versions:

1. Video tutorial method: This method involves creating a batch file that sets the JAVA_HOME environment variable to the desired JDK version. You can then run this batch file before starting the project. You can find a video tutorial on how to create a batch file for switching between JDK versions on Windows here.
2. Directories method: This method involves changing the system PATH environment variable to point to the desired JDK version. You can find a detailed guide on how to switch between JDK versions using the directories method here.

Understanding Java SE 8 and Java SE 19

Java SE (Standard Edition) is a platform that provides a comprehensive set of APIs for developing and deploying Java-based applications. Java SE 8 is the eighth major release of Java SE and includes two products: JDK 8 and JRE 8. JDK 8 includes the Java Development Kit, which is needed for developing Java-based applications. JRE 8 includes the Java Runtime Environment, which is needed for running Java-based applications.

Java SE 19 is the latest version released in September 2022. It includes several new features and improvements such as improved garbage collection, new APIs, and enhanced security.

Additional Information

Here are some additional information and tips related to JDK:

• You can download the latest version of JDK from the official website.
• If you need to use an older version of Java, you can find the archive of Java SE downloads here.
• To verify the IDE’s actual JDK version, you can follow the instructions provided by the IDE vendor.
• Java 8 and JDK 1.8 are the same thing. The “1.” prefix was dropped with the release of Java SE 9.

Best Practices for Java Programming

Writing readable and maintainable code is crucial for software development. Here are some best practices for java programming:

• Use appropriate data types for variables and methods.
• Follow naming conventions for classes, methods, and variables.
• Use comments to explain complex code.
• Use exception handling to handle errors and unexpected situations.

Troubleshooting Java-Related Issues

Here are some common Java-related issues and tips for troubleshooting them:

• ClassNotFoundException: This error occurs when the JVM cannot find a class that is required to run the application. To fix this error, ensure that the class is present in the classpath.
• OutOfMemoryError: This error occurs when the JVM runs out of memory. To fix this error, increase the heap size using the -Xmx flag.
• NullPointerException: This error occurs when a null reference is used in the code. To fix this error, ensure that all variables are properly initialized.

Here’s a cheatsheet for some commonly used Java commands:

• javac : Compiles Java source code to bytecode.
• java : Runs a Java application.
• jar : Creates a Java archive file.

Improving Java Performance

Using the latest version of Java can improve performance and security. Older versions of Java may have security vulnerabilities and performance issues. Here are some tips for improving java performance:

• Use the latest version of Java.
• Use the appropriate garbage collector for your application.
• Use profiling tools to identify performance bottlenecks.
• Use a caching mechanism to reduce the number of database queries.

Popular programming languages that use the JVM include Bash, PHP, Python, Go, Java, C#, NodeJS, and Javascript.

Other quick code examples for checking Java JDK versions

In Java , in particular, how to get java version in java code example

System.getProperty("java.version")

Conclusion

In this article, we discussed how to check the version of JDK installed on your computer. We covered various methods, including checking through command line, uninstalling all versions of Java before installing JDK 8, and switching between multiple JDK versions on Windows. We also discussed Java SE 8 and Java SE 19, additional information related to JDK, best practices for Java programming, troubleshooting Java-related issues, improving Java performance, and popular programming languages that use the JVM. Checking JDK version regularly is important for compatibility and security reasons, and we encourage you to follow the best practices for Java programming to write better code.

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