How to Fix “Java Runtime Environment not found” error {Windows 10 and Ubuntu 20.04}

In this post, we will solve the “Java Runtime Environment not found error”. This java error is one of the common errors faced by developers or end-users. Whenever you try to install any software which requires java like eclipse or Minecraft. Also, if you are new to java development, JDK or Java Development Kit is necessary for you.

Following this tutorial will help you to resolve all Java runtime errors. Additionally, you will learn to install, remove and set java variables in Windows10 and Ubuntu.

These are the very common errors you will find related to Java.

  • java runtime environment not found
  • java runtime environment not found windows 10
  • eclipse java runtime environment not found
  • eclipse java runtime environment not found path
  • java SE runtime environment not found
  • java runtime environment not found at bin javaw.exe
  • unable to load java runtime environment
  • cannot determine a valid java home
  • java runtime environment not found mac

Let’s understand some basic concepts of Java runtime first. Check out this post, if you are getting a java command not found error.

What is a runtime environment?

Runtime basically means everything you require to run a program. Which includes environment variables, directory structure, common libraries etc. This can also be a virtual machine like

  • JRE (Java Runtime Environment)
  • CLR (Common Language Runtime) for .net framework

The target would be JRE or CLR for your program, need to decide by you. As soon as you execute any program, it’s in run time.


Stands for Java Runtime EnvironmentStands for Java development kit
To run Java programs, you need JREHelps to build Java programs and applets
Platform dependent contains libraries and supporting toolPlatform dependent contains tools development and debugging
JRE does not contain a development kit.JDK includes JRE also to execute the program

What are the causes of the “Java Runtime environment not found” error

  1. Java is not installed in your system
  2. Java installation not completed (due to errors)
  3. Environment variables of Java are not set
  4. Java conflict due to more than one Java Runtime installation

Because JRE is platform-dependent, I have covered java installation, variable setup and un-installation for Windows and Ubuntu both.

Choose Windows 10 or Ubuntu 20.04 from the post and follow step by step to get java issues resolved.

Java download

Before installation, first, we need to download java


Visit and download JDK 15 or the latest available for your system. I am downloading it for Windows 10 (64-bit). The latest available versions of java are listed in the screenshot.


How to install Java runtime environment step by step

Let’s solve 1st reason for “Java runtime environment not found”, Because java is not installed.


First, check for any pre-installed java version –

Open the command prompt with “Run as administrator” and run java command.

C:\Users\admin> java --version

How to install java runtime environment in Windows 10


Once Download completes. Browse to the “jdk-15.0.1_windows-x64_bin.exe” file and double-click on it, to run the installer. Click Next.



I recommend keeping “C:\Program files\java\jdk-15.0.1 (64-bit)” as the default installation folder. Select Next.

You may select different installation folders also. For example, if you are installing a second instance of java software. Click on change and browse for the target folder.



Let installation complete, it may take a few minutes.



Click close. Now you are done with java installation on windows 10.


How to set the environment variable for java in windows10

Set the Environment variable for java in windows 10 by these steps –


Type “environment” in the search window. Click “open” on “Edit the system environment variables



Click on Environment variables.



Select “Path” > Then click Edit.



Select New > Give path of java installation directory > For example, “C:\Program files\java\jdk-15.0.1\bin” in my case. If you have selected a different folder for java installation in step4. You can enter your path to the bin folder.

Click OK.



Set “classpath” for java. Click “New” in the environment variable window. It allows to set up the new environment variables.



In “Variable name”, enter “classpath“. Also in “variable value” provide path to your java installation till “lib” folder. In my case it is “C:\program files\java\jdk-15.0\lib > Select OK


Close all open environment variables windows by selecting OK.

How to check what version of java I have?

Installation and java variables have been set up. Now, Let’s validate the java installation and version.


Open the command prompt with “run as administrator” rights in windows 10.



Run the “java” command to check your Java and JRE (Java Runtime Environment) version.

java --version

Check java SDK version with javac command

javac version

Video tutorial-JRE error solved for Windows

“Java Runtime Environment not found” error fixed for windows 10

How to uninstall java from Windows 10

In case, you are not happy with your old java or JRE version and want to install a new. For that, you need to remove the old Java version.

Cleanup of Java from Windows 10 is pretty easy. Follow these steps to remove java from your system.


Search add or remove programs and click open



Select the java program and click Uninstall.


Java software will go from the window. You can clean up java variables also, set up in step10 and 11 earlier.

How to install java runtime environment in Ubuntu 20.04

There are two ways to download and install java or JDK in Ubuntu 20.04

A.) Using the apt command

B.) Download the Oracle JDK package and install it manually

Let’s see both options one by one-

A.) How to install java or JRE in Ubuntu 20.04 using the apt command

To install Java in Ubuntu using the repository, Follow these commands


Update package index using apt command

$ sudo apt update


Check if you have any old java versions installed in the system. In my case, java is not installed.

$ sudo java -version


Command ‘java’ not found, but can be installed with:

sudo apt install openjdk-11-jre-headless              # version, or
sudo apt install default-jre                                      # version 2:1.11-72


Run the “apt” command to install java or JRE. I will install default-jre version 2:1.11-72 in my Ubuntu system from the list.

$ sudo apt install default-jre

Select “Y” and press Enter. Let installation complete. it will take a few minutes.


Check the java version

$ sudo java -version



How to Remove java from Ubuntu 20.04


Run apt command to remove JRE package installed. Press Y and then enter.

$ sudo apt autoremove "JRE package name"

B.) How to install the latest java or JDK in Ubuntu 20.04 from oracle (manually)


Java JRE download steps –

Visit and download JDK 15 or the latest available .deb and transfer to your system. I am downloading Debian package jdk-15.0.1_linux-x64_bin.deb.


Alternatively, you can download java using wget command.

$ sudo wget "download link"

Reference output



Rename the .deb file using mv command, if required. Then install the Debian package using the dpkg command.

Learn more ways to install .deb package.

$ sudo dpkg -i ".deb-file-path"



Default installation directory path of java would be “/usr/lib/jvm/jdk-15.0.1/“. So, make a note of it, as it will be required to set up a Java_HOME variable.

How to set the “JAVA_HOME” variable in Ubuntu 20.04

Set the JAVA_HOME variable for all users in Ubuntu by editing the environment file.


Edit /system/environment file

$ sudo vi /etc/environment

Add path “/usr/lib/jvm/jdk-15.0.1/bin” to the last of the environment file. Then, save and exit.


Run source command to execute changes made in the environment file.

$ sudo source /etc/environment


Check your java version

$ sudo java -version

Remove java runtime environment package using dpkg command


Run the dpkg command with the –purge option to completely clean java from Ubuntu 20.04

$ sudo dpkg --purge "package-name"

For example,

$ sudo dpkg --purge jdk-15.0.1

Video TutorialJRE error solved for Ubuntu

Video on “How to fix java runtime environment error in Ubuntu 20.04”

Frequently Asked Questions (FAQs)

Where is the java runtime environment on Windows 10?

The default installation folder for java runtime is “C:\Program files\java\jdk-15.0.1\bin” in the case of windows 10.

What does Java Runtime Environment do?

Java Runtime Environment (JRE) helps to run java programs like the eclipse.

What is the java runtime environment used for?

Java runtime environment helps to run java programs like Tomcat, eclipse and Jenkins.

What is the java runtime environment?

Java runtime environment JRE is a software that runs on the operating system. Which provides class libraries and resources to run java programs.

How to set the java runtime environment in windows 10?

Type “environment” in the search window. Click “open” on “Edit the system environment variables
Click on Environment variables.
Select “Path” > Then click Edit.
Select New > Give path of java installation directory > For example, “C:\Program files\java\jdk-15.0.1\bin
Click OK

Ending notes

I hope after reading this article, you will be able to solve the “Java Runtime Environment not found error”. Because majorly reasons for java related errors are, either Java is not installed or the java variable is not set.

if you still have issues, please comment and let me know, I will try to help you.


I'm Dev, your friendly neighbourhood Tech Savy. I spend my days with gadgets, servers, and the occasional laugh-inducing software mishap. Think of me as your tech-savvy, glitch-prone buddy. If you've got questions, feedback, or just need someone to blame when your Wi-Fi goes haywire, I'm your guy!

This Post Has 2 Comments

  1. Ollie Figs

    Unable to locate the Java runtime.
    Error details: The operation completed successfully.

    Filename on disk: jdk-16.0.1
    Path: C:\Program Files\Java\jdk-16.0.1
    Exists: Directory\

    I keep getting this message when trying to run mod on minecraft through curseforge

    1. Dev

      May be due to the conflict with default runtime provided and installed Java runtime on your system. Try deleting the runtime folder from your installation directory. It may fix the issue. “\Local Disk > Program Files (x86) > Minecraft”, Delete the runtime folder inside it.
      I hope it helps.

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