JAR: how to open these files in Windows 10

If you have come across the JAR file type online and have wondered what it is, you have come to the right place. It is a Java Archive and here we will talk about what they contain and how to open them. Also, you may find errors when trying to open a JAR file; We also have solutions for that.

What are JAR files?

JAR means Java ARchive. As the name implies, it is a storage file; a single file that contains other files packaged for reasons such as portability and to decrease storage space.

If you are familiar with ZIP files, then a JAR file is essentially the same. The difference is that these files are applications designed to be used by the Java Runtime Environment.

The unique element of the JAR files is that they contain a manifest. This is a special meta file that simply tells the JAR how to behave and contains information about the files inside.

This class of files can also contain files called CLASS (compiled Java code). As well as audio files, image files and more. This file can be read and executed as a single request by the runtime environment.

It can be used for all kinds of purposes on desktop computers and mobile devices. For example, it could be a game, an application theme or a browser add-on.

How to open JAR files

If you want to run one of these files, that is, run the actual application it contains, then you need to install the Java Runtime Environment. You may already have it on your computer, but get it back from the official site. To make sure you are running the latest version.

Then, you must download a utility called Jarx. This makes JAR files behave like common programs on your computer. As such, once Jarx is installed, you can open a JAR file like any other by double clicking on it.

You can also run it from the command prompt. Click Search and type "cmd." Right click on the result of the command prompt and select Run as administrator to open the window. Then, enter the following command, but replace sample.jar with the full path of the JAR file:

java -jar sample.jar

Extract files of this type

Alternatively, you can unpack files of this type. You can do this to see what information it contains, or if the JAR file is not designed to be an executable file.

To unpack these files, you need a program that can extract compressed files. Windows includes the functionality for this, but you can also use file extraction software such as 7-Zip or WinRAR to do the job.

Open the file in question within the software and you can browse all the folders and files within it. Also, you can extract the JAR if you want to use or inspect more individual files.

Do you want another file opener when you don't have a program installed? You can use an extractor online if you don't want to download another program. Of course, make sure you choose one that supports the JAR format because not everyone will.

A good option is Archive Extractor. Simply load your file in question and it will show you the content of the file within a tree structure. Click on a folder to open or expand it and a file to download it individually.

Finally, if your computer has trouble recognizing an executable JAR file, you can right-click on the file, click Rename and then add the .ZIP file extension. This works because the file types are closely linked.

How can you make this kind of files?

Are you sure you need to make a JAR file? Remember, they have a specific purpose: to group files to use as a Java application.

If that is what you need to do, go to the Oracle packaging programs in the documentation of files of this type. This will give you all the information you need on how to create, package and sign a JAR file.

How to troubleshoot when opening these files

You may receive an error when trying to open a file in question. It is often due to incompatibility or security settings.

Update Java Runtime Enviroment

You should always run the latest version of Java Runtime Environment.

To see which version of Java you are running, open the Start menu and type "java settings" and select the result. The Java Control Panel will open.

On the General tab, click on "About …" and verify that the version you are running is the latest available directly from the Oracle website. If not, download and update it.

JAR opens in the wrong program

Windows may not know what to do with this type of file and could try to open it in a program that is not compatible with the format.

To solve this, right-click on the file and go to "Open with." There are a number of default programs to choose from and one of these could be the right one. Otherwise, click on "Choose another application".

If you want to run the file directly in the Java Runtime Environment, go to: Program Files Java jre1.8.0_211 bin and select java.exe.

JAR gives security error when opening

Java has been seen as a security risk in recent years, so don't be surprised if you receive a warning when trying to open a JAR file.

To solve this, open the Start menu and type "java settings". Now select the result. The Java Control Panel will open. Click on the Security tab. Make sure you have enabled: "Enable Java content for the browser and Web Start applications".

Set the security level to High and add to the list of exception sites if necessary. Once this is done, click OK.