Java virtual machine: installation and launch. Java Virtual Machine

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Java virtual machine: installation and launch. Java Virtual Machine
Java virtual machine: installation and launch. Java Virtual Machine

Virtual machines have long ceased to be some kind of abstract concept and today are accessible and understandable to any user. One of the most necessary of its kind is the Java virtual machine (JVM), which is installed on Windows systems initially during the first installation of the OS itself. However, quite often it is necessary to install it yourself, supplement or update the components of an existing platform. Further, it is proposed to figure out what it is in general, what it is for, how to install the necessary components yourself and solve some problems associated with starting a VM on Windows systems.

What is the Java Virtual Machine?

Let's start by defining what this platform really is, so that uninformed users will immediately understand why it is required to install it on their own computers. In its general sensethis platform and its components are usually used to execute all sorts of scripts and applets written in the Java programming language when you visit Internet sites containing related content. And these can be multimedia elements in all manifestations, some simple games, add-ons for using banking services, interactive maps, etc.

Besides, support for this platform is actively used in almost all mobile phones, even if they have their own operating systems. Have you ever noticed that on old phones that did not have modern operating systems like Android or iOS, you could easily install applications (most often games) from JAR and JAD files? It was Java support that made it possible. And today such support is available in all mobile systems.

Finally, it is worth noting separately that the Java Virtual Machine is essential for many programmers and web designers to develop their own applets and applications. Thus, it becomes quite obvious that it is necessary to have it on your computer in any case.

However, users who do not understand the intricacies of using the Java Virtual Machine will be surprised that it will not be possible to just start it. Yes, indeed, this is true, since the main executable environment itself does not have a graphical interface, and you can use it only through integration into web browsers installed on your computer or laptop, or bundled withIDE.

Pre-check installed version

First, let's check if the Java VM environment is installed on your system. To check, call the command console (cmd) in any way convenient for you (not necessarily on behalf of the administrator), and then run the command java –version.

Checking the Installed Java Version
Checking the Installed Java Version

If the environment is installed, the information shown in the image above will be displayed, where the paramount attention should be paid to the version of the platform. Since it is not always updated automatically even when installing updates for Windows systems themselves, it is strongly recommended to perform such an update manually by downloading the necessary content from official resources and then installing it yourself.

What do you need for work?

In general, it should be said separately that the Java Virtual Machine is only one of many components of the entire platform. So, those who create applications need to install a specialized JDK (Java Development Kit) developer package, and an ordinary user will only need to have an executable JRE environment where it will be impossible to create their own applets, but it will be possible to launch and use ready-made programs written in Java. But if you want to become a qualified developer, you may need to pick up an IDE kit for yourself (at the moment, Eclipse and NetBeans are the most common and recommended for installation and use).

Where and whatdownload for installation on Windows?

Java VM installer download
Java VM installer download

For downloading the components required to install or upgrade the Java Virtual Machine, you can visit, where the download section will prompt you to download the appropriate installer for your operating system.

Selecting components to download
Selecting components to download

If you need additional components, you can go to, where the complete Java SE (JDK) version 12, some older platform modifications, and NetBeans are currently available.

Here it is worth giving a little explanation, because many users may have doubts about which kit to download, because there are three modifications on the site! You will most likely only need the SE version, since EE is an enterprise-oriented development environment, while ME is a similar platform for working with mobile systems.

Installing the Java Virtual Machine

So, we assume that the installer is downloaded from one of the official sources on the user's computer.

Running the Java SE Installer
Running the Java SE Installer

The Windows 10 Java Virtual Machine installer (as in the example below) must now be run as administrator (unless your built-in superuser account is deactivated).

Java SE installer
Java SE installer

In the initial installation window, you can not change anything, just click the buttoninstallation confirmation, after which the process of copying files starts to integrate all the necessary components into the system.

Remove obsolete platform components
Remove obsolete platform components

When the main components are copied, you must agree with the uninstallation of obsolete components (if any) and click the appropriate button (Uninstall). At the end, you will need to click the continue button again, after which a message about successful installation will appear.

Note: keep in mind that the applet responsible for tracking updates will immediately be added to the system startup section. As unnecessary, you can disable it using the appropriate section either in the configuration (msconfig) for Windows 7, or in the Task Manager (taskmgr) for Windows 8 and 10.

Error creating platform

Finally, the platform is installed. Now let's pay attention to some failures and errors that may appear after the integration of components into the system is completed. The very first and most common problem is the inability to start the Java virtual machine (for Windows of the latest generations, this problem is usually not observed, but in systems that are no longer supported, such as XP, they can manifest themselves).

To fix the problem, use the properties of the computer, go to advanced settings, enter the environment variables section, create a new setting with the name and value shown in the image below.

Setting Environment Variable Options
Setting Environment Variable Options

In the example, the specified valuecorresponds to 512 MB of allocated RAM that the machine is allowed to use. You can increase it if necessary.

Error opening registry keys

Sometimes the Java Virtual Machine for Windows 7 and above can throw a registry access error, especially when running from the command line. In this situation, you need to access the System32 directory and remove the three executable EXE files with the following names: java, javaw, and javaws. After that, you just need to reinstall the environment using the previously downloaded installer file.

Main class search failed

Another crash in which the virtual machine spontaneously and crashes can be fixed in the following way.

Malicious Software Removal Tool
Malicious Software Removal Tool

First run the Malware Finder and Removal Tool by typing mrt in the Run console, click the continue button, and then select full scan. At the end of the process, completely reboot the system, then enter the configuration (msconfig) or Task Manager, and then deactivate the startup component called WJView.exe in the list. After that, the system must be restarted without fail.

Error opening JAR files

Finally, the error related to the impossibility of opening JAR format objects corresponding to the platform and virtual machine is corrected in the following way.

Selecting default programs
Selecting default programs

In the "Control Panel" (control), enter the sectiondefault programs, click the link for file type or protocol associations to individual programs, select the.jar extension from the list, click the change program button, and select the Java Virtual Machine. If the issue persists, try a complete reinstall of the entire platform.

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