File Extension Database

Open JAR File

JAR file extension is most commonly associated with a Java Archive, which is often used to package and distribute Java classes and metadata in development environments. JAR files may also be found to contain themes and add-ons for Mozilla's Firefox web browser or Thunderbird E-Mail client.

JAR files are standard Zip compressed archives which contain the classes and associated resources of a program as well as a manifest file which determines how the JAR file is handled. A manifest which defines a contained class as the main class will be treated as a standalone application, for example. The manifest can also contain links to other JAR files to be loaded upon execution, though this does rely on the paths to additional resources remaining the same as when the package was created. JAR files also support digital signing, whereby signature information is added to the manifest file and read when the file is opened. This prevents the contents being altered, as changing any of the enclosed files will result in a non-matching digital signature. It is also possible to digitally sign individual CLASS files, with any that do not have a valid signature being rejected by the Classloader of the Java Virtual Machine, preventing malicious code being injected into existing JAR packages.

JAR files are executed if the host machine has the Java Runtime Environment (JRE) installed, and should not be opened if the source is unknown as it is possible that the contained program is malicious.

You can open JAR files on a machine with the Java Runtime Environment installed, which is available on the Windows, Solaris, Mac and Linux platforms. JAR files may also be opened in web browsers with Java support. Alternatively, JAR packages can be opened using any archiving software with unzipping capabilities and the contents extracted, though most resources are already compiled and therefore not human-readable.

Typical JAR application file locations:

C:\Program Files (x86)\Java\jre6\bin\javaw.exe -jar "%1" %*
"C:\Program Files (x86)\Java\jre6\bin\javaw.exe" -jar "%1" %*

Frequently used application names to open JAR files:

Java

Frequently associated Windows objects:

jarfile

How Can I Open JAR File on Windows

We researched and learned that the best way to open JAR file is to find a JAR file in question in Windows OS File Explorer and double click on it to launch the corresponding application.
If a JAR file is not opened in an application and you instead get a "Windows can't open a file" error message you should try looking for an application which can open the file in question.
If you know the application which can open JAR file then run it and see if there is a File->Open main menu option in the application.
If you don't know the application which function as JAR file opener then try to search online for "JAR viewer", "application to open JAR file" or "open JAR file" queries in the search engine you like.
Install the application you found and check if it can open JAR file

How Can I Open JAR File on Mac OS

We recommend to find a JAR file in question in Mac OS Finder and double click on it to launch the corresponding application.
If a JAR file is not opened in a Mac OS application and you instead get a "There is no application set to open the file" error message you can click on "Search App Store" in the error dialog and Mac OS will show you applications compatible with JAR file.
If you know the Mac OS application which can work as JAR file opener you can choose the "Choose Application..." option in the error box to associate the file extension and open JAR file in it.
If you don't know the application which can open JAR file then try to search for "JAR viewer", "application to open JAR file" or "read JAR file" queries in the online search engine you like.
Install the application you found and check if it can read JAR file

How Can I Open JAR File on Android

If you downloaded a JAR file on Android device you can open it by following steps below:

In the Android apps list on your Android device find "My Files" or "File manager" app and tap to start it.
Tap on "Downloads" folder inside the app.
You should see your downloaded JAR file in that folder.
Tap on the file. If Android device supports opening the file you downloaded it will open in the corresponding app.
If file does not open you can look for the corresponding app that can open the file by searching Android App Store for the "JAR".
If you cannot open the file with the apps from Android App Store it is possible that the file could only be opened on desktop platforms such as Windows or Mac OS. Try searching for "JAR viewer", "JAR file reader" online and see if any desktop applications can open it.
It is also possible that the file you downloaded is outdated and is no longer supported.

How to Open JAR File on iPhone or iPad

To open JAR File on iOS device follow steps below:

We advies to open Files app on your iPhone or iPad device. You can find it by swiping down on the home screen and typing "Files" in the search bar.
Tap on the Downloads folder on the Files app home screen.
You will see all files that you recently downloaded. Tap on the JAR file to view it.
If you have the right app that can open it it will automatically launch and open your file.
If you don't have the app which can open it you need to serch Apple app store for "JAR". This way you can find apps which can open JAR files.
If this doesn't help it is possible that your file could be opened only by the desktop application. To find an app which can open it on desktop look for "JAR viewer" or "JAR file" online in your favorite search engine.