JAR File Extension

What is JAR file?

Files with the JAR extension are files of archives compressed in the ZIP package, used by the JRE – Java Runtime Environment programming environment. JAR packages contain metadata files and files containing resources, such as texts, images or other types of data, packed into a single file, possible to be used with the Java environment.

Additional information

JAR package can be also a separate Java application, if it has a specified main class. A JAR file enables the executable environment to efficiently apply classes of applications and related resources, which highly increases speed of functioning. Each, singular element of JAR packages can be also further compressed, which highly reduces weigh of packages and enables to send them quickly.

Among metadata of a JAR file, there can be a manifest file, which defines the method of utilisation of a given package. There can be also a digital signature within a manifesto.

Content of a JAR file

In order to browse through the content of a JAR file, you can use any popular tool for files decompression, and perform the same actions as in case of a standard ZIP archive. You can also use the command line and the jar tool: "jar -xf file.jar”.

Programs which support JAR file extension

Below you will find an index of software programs that can be used to open JAR files divided into 3 categories according to system platform supported. JAR files can be encountered on all system platforms, including mobile, yet there is no guarantee each will properly support such files.

Updated: 07/29/2019

How to open file with JAR extension?

Problems with accessing JAR may be due to various reasons. On the bright side, the most encountered issues pertaining to Java Archive Format files aren’t complex. In most cases they can be addressed swiftly and effectively without assistance from a specialist. The list below will guide you through the process of addressing the encountered problem.

Step 1. Download and install Java Runtime Environment

Problems with opening and working with JAR files are most probably having to do with no proper software compatible with JAR files being present on your machine. This issue can be addressed by downloading and installing Java Runtime Environment or different compatible program, such as Web browser, WinZip, Eclipse. The full list of programs grouped by operating systems can be found above. If you want to download Java Runtime Environment installer in the most secured manner, we suggest you visit website and download from their official repositories.

Step 2. Verify the you have the latest version of Java Runtime Environment

If the problems with opening JAR files still occur even after installing Java Runtime Environment, it is possible that you have an outdated version of the software. Check the developer’s website whether a newer version of Java Runtime Environment is available. Sometimes software developers introduce new formats in place of that already supports along with newer versions of their applications. This can be one of the causes why JAR files are not compatible with Java Runtime Environment. All of the file formats that were handled just fine by the previous versions of given program should be also possible to open using Java Runtime Environment.

Step 3. Assign Java Runtime Environment to JAR files

If the issue has not been solved in the previous step, you should associate JAR files with latest version of Java Runtime Environment you have installed on your device. The next step should pose no problems. The procedure is straightforward and largely system-independent

Change the default application in Windows

• Right-click the JAR file and choose Open with option
• Next, select the Choose another app option and then using More apps open the list of available applications
• The last step is to select Look for another app on this PC option supply the directory path to the folder where Java Runtime Environment is installed. Now all that is left is to confirm your choice by selecting Always use this app to open JAR files and clicking OK.

Change the default application in Mac OS

• Right-click the JAR file and select Information
• Proceed to the Open with section. If its closed, click the title to access available options
• Select Java Runtime Environment and click Change for all...
• If you followed the previous steps a message should appear: This change will be applied to all files with JAR extension. Next, click the Continue button to finalize the process.

Step 4. Ensure that the JAR file is complete and free of errors

Should the problem still occur after following steps 1-3, check if the JAR file is valid. Problems with opening the file may arise due to various reasons.

1. Verify that the JAR in question is not infected with a computer virus

If the JAR is indeed infected, it is possible that the malware is blocking it from opening. Scan the JAR file as well as your computer for malware or viruses. JAR file is infected with malware? Follow the steps suggested by your antivirus software.

2. Ensure the file with JAR extension is complete and error-free

If the JAR file was sent to you by someone else, ask this person to resend the file to you. It is possible that the file has not been properly copied to a data storage and is incomplete and therefore cannot be opened. When downloading the file with JAR extension from the internet an error may occurred resulting in incomplete file. Try downloading the file again.

3. Check if the user that you are logged as has administrative privileges.

Some files require elevated access rights to open them. Log in using an administrative account and see If this solves the problem.

4. Make sure that the system has sufficient resources to run Java Runtime Environment

If the system is under havy load, it may not be able to handle the program that you use to open files with JAR extension. In this case close the other applications.

5. Check if you have the latest updates to the operating system and drivers

Up-to-date system and drivers not only makes your computer more secure, but also may solve problems with Java Archive Format file. It may be the case that the JAR files work properly with updated software that addresses some system bugs.

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