A JNLP file isn’t a document; it’s a small instruction file that tells Java Web Start to download and run a Java application. Windows 11 can’t open it on its own, and current versions of Java no longer include Web Start. The simplest fix is to install OpenWebStart, a free replacement, and then double-click the JNLP file. Older setups that still use Java 8 can open it with Java’s own javaws program.
Applies to: Windows 11 and Windows 10. Last reviewed October 7, 2026.
Only open JNLP files from sites you trust, such as your employer, school, bank or a server you manage. A JNLP file can launch a full program on your PC.
What is a JNLP file?
JNLP stands for Java Network Launch Protocol. The file is plain text (XML) that lists where to download a Java program and how to start it. You usually get one by clicking a “Launch” button on a website, for example to open a server’s remote console, an older business app, or a government or banking tool.
Method 1: Use OpenWebStart (recommended)
- Download OpenWebStart for Windows from openwebstart.com and run the installer.
- Accept the default settings, including the option to associate .jnlp files with OpenWebStart.
- Double-click the JNLP file. OpenWebStart downloads a suitable version of Java if needed, then starts the application.
- Approve any security prompt if you trust the app’s publisher.
If double-clicking still does nothing, right-click the JNLP file, select Open with > Choose another app, pick OpenWebStart and tick Always use this app.
Method 2: Use Java 8 and javaws
Java 8 was the last version from Oracle to include Java Web Start. If an app’s instructions specifically call for Java 8:
- Install Java 8 from the official java.com site. Workplaces may need a commercial license; check with your IT department.
- Right-click the JNLP file and select Open with > Choose another app > Choose an app on your PC.
- Browse to
C:\Program Files\Java\jre1.8.0_xxx\bin\javaws.exe(or the same path under Program Files (x86)) and select it. - If Java blocks the app, open Configure Java from the Start menu, go to the Security tab and add the site’s address to the Exception Site List.
Old Java versions have known security holes, so keep Java 8 updated and remove it when you no longer need it. For the developer kit, see how to install the JDK on Windows 10.
Method 3: See what the file launches
Right-click the JNLP file and choose Open with > Notepad. Look for the codebase and href lines, which show the website the app comes from, and jar lines, which list the program files. This helps you confirm the file is genuine before running it.
Remote server consoles (iDRAC, iLO and similar)
Many server management pages used JNLP files for their virtual console. Newer firmware usually offers an HTML5 console that runs in the browser without Java. Check the console settings for an HTML5 option, or update the server’s firmware, before setting up Java.
Troubleshooting
The browser saves the JNLP file but nothing happens
Browsers don’t run JNLP files themselves. Open your downloads (Ctrl + J) and double-click the file once OpenWebStart or Java 8 is installed.
“Application Blocked by Java Security”
The app isn’t signed in a way Java trusts. Add the site to the Exception Site List (Method 2, step 4), or ask the app’s provider for an updated version.
The JNLP file is old and fails to download parts
JNLP files often expire because they contain one-time session details. Go back to the website and click Launch again to get a fresh file.
Frequently asked questions
Is a JNLP file the same as a JAR file?
No. A JAR file is the Java program itself; a JNLP file tells Java where to get it. See how to open a JAR file on Windows 10.
Do I need JavaScript enabled?
No. JavaScript and Java are unrelated. For browser settings, see how to enable JavaScript on Windows 11.
Matt Jacobs has been working as an IT consultant for small businesses since receiving his Master’s degree in 2003. While he still does some consulting work, his primary focus now is on creating technology support content for SupportYourTech.com.
His work can be found on many websites and focuses on topics such as Microsoft Office, Apple devices, Android devices, Photoshop, and more.