File Extension Database

Open JNLP File

JNLP file extension is used by the Java run time environment to launch 'Web Start' applications. The Java Network Launching Protocol (JNLP) was specifically designed for these applications and is defined with an XML schema. Unlike regular web applets, these applications do not run in the web browser but are downloaded onto the user's computer and executed as a normal Java application (with some restrictions). This enable developers to get around a lot of compatibility issues with web browser Java plugins and different Java Virtual Machines (JVM).

The JNLP file itself is a human readable file containing settings and configuration information formatted with XML. This information includes the location of the application's jar file, the name of the main class and any additional parameters and set up information the application needs to work correctly.

All you need to open JNLP files is a JNLP client such as Java Web Start, which is installed with the Java run time environment from Sun Microsystems. This software will automatically parse the JNLP file and run the associated Java application. The JNLP client can even be installed automatically on the user's machine if they don't already have one, and the user will simply see the Web Start client download and install prior to running the Java application in these cases.

There have been a number of security issues surrounding the use of JNLP. For instance, one vulnerability was found that used a specific JNLP file to cause a buffer overflow in the Web Start client, enabling the attacker to execute malicious code with the privileges of the currently logged in user. On home user's Windows systems, this generally means administrator rights. The application could therefore do anything it liked on the user's computer. This vulnerability has since been fixed, but you should still be careful of executing any application from the internet unless it is from a trusted source.

If needed you can open JNLP file using a text editor to quickly look what is inside.

Typical JNLP application file locations:

C:\Program Files (x86)\Java\jre6\bin\javaws.exe "%1"
"C:\Program Files (x86)\Java\jre6\bin\javaws.exe" "%1"

Typical JNLP mime types:

application/x-java-jnlp-file

Frequently used application names to open JNLP files:

Java

Frequently associated Windows objects:

JNLPFile

How Can I Open JNLP File on Windows

We researched and learned that the best way to open JNLP file is to find a JNLP file in question in Windows OS File Explorer and double click on it to launch the corresponding application.
If a JNLP 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 JNLP 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 JNLP file opener then try to search online for "JNLP viewer", "application to open JNLP file" or "open JNLP file" queries in the search engine you like.
Install the application you found and check if it can open JNLP file

How Can I Open JNLP File on Mac OS

We recommend to find a JNLP file in question in Mac OS Finder and double click on it to launch the corresponding application.
If a JNLP 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 JNLP file.
If you know the Mac OS application which can work as JNLP file opener you can choose the "Choose Application..." option in the error box to associate the file extension and open JNLP file in it.
If you don't know the application which can open JNLP file then try to search for "JNLP viewer", "application to open JNLP file" or "read JNLP file" queries in the online search engine you like.
Install the application you found and check if it can read JNLP file

How Can I Open JNLP File on Android

If you downloaded a JNLP 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 JNLP 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 "JNLP".
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 "JNLP viewer", "JNLP 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 JNLP File on iPhone or iPad

To open JNLP 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 JNLP 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 "JNLP". This way you can find apps which can open JNLP 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 "JNLP viewer" or "JNLP file" online in your favorite search engine.