How to Set Windows File Associations to Open .JNLP Files

Document Details:
To modify the file association to have JNLP files open with Java Web Start on a Windows XP, Windows 7/Windows Vista, Windows 8, or Windows 10 computer, follow the steps below:

Windows 10:

• Go to the nhdeeds.com website, then click on Search County Records.
• Click to Accept Registry Disclaimer, then click the link to Launch the search application 
• When prompted to open or save, choose save
• Navigate to the saved location to right-click on the saved .jnlp file and choose Open With 
• Make sure there is a check-mark in the box that says Always use this app to open .jnlp files, then click More apps 
• Scroll down to the bottom and select Look for another app on this PC 
• Select the Java folder, (If you do not see Java, go back up one level to the c:/ drive and select Program Files(x86), then select the Java folder. If you do not have a Java folder here, you will want to go to www.java.com and download the latest version before continuing with these steps.) 
• Double click the latest jre folder (example: jre7, jre1.8_191, etc) 
• Double click the bin folder 
• Double click the javaws application 
• Click the Close button. JNLP files will now open, by default, with Java Web Start

Windows 7 and Vista:

• Click on Start and select Control Panel. 
• In the top right corner of the Control Panel, select Category from the view by: pull down menu. 
• Click the Programs link. 
• Under Default Programs, click the Make a file type always open in a specific program link. 
• Under the Name column, locate and select JNLP from the list of Extensions. 
• Click the Change program button. 
• From the Open With window, click the Browse… button.. 
• From the Open With… dialogue window, (This will typically open in the c:\Program Files directory)
• Select the Java folder, (If you do not see Java, go back up one level to the c:/ drive and select Program Files(x86), then select the Java folder. If you do not have a Java folder here, you will want to go to www.java.com and download the latest version before continuing with these steps.) Double click the latest jre folder (example: jre7, jre1.8_191, etc)
• Double click the bin folder
• Double click the javaws application
• Click the OK button.
• Click the Close button.
• JNLP files will now open, by default, with Java Web Start.

Windows 8:

• Open Default Programs by swiping in from the right edge of the screen, tapping Search (or if you’re using a mouse, pointing to the upper-right corner of the screen, moving the mouse pointer down, and then clicking Search), entering Default programs in the search box, tapping or clicking Apps, and then tapping or clicking Default Programs.
• Click Associate a file type or protocol with a program.
• Locate .JNLP under the list of registered file types. Highlight the JNLP file by tapping or clicking .JNLP under the Extensions column, then tap or click on Change Program. 
• Tap or Click Java™ Web Start Launcher from the list of programs. 
• If you do not see Java Web Start Launcher listed, tap or click More options then Look for another app on this PC. 
• Tap or double-click on Local Disk (C:) in the left column (located under “Computer”). 
• Tap or double-click Program Files (x86). If you do not see this, select Program Files instead. 
• Locate and select the Java folder. 
• Select the latest JRE folder (JRE6 or JRE7 or jre1.8_*).
• Select bin. 
• Select javaws.exe and press Open. 
• JNLP files will now open, by default, with Java Web Start.

 Windows XP:

• Click on Start and select Control Panel from the Settings menu (or click Start and select Control Panel). 
• In the control panel, click Folder Options . 
• In the Folder Options window, click the File Types tab. 
• Locate JNLP under the list of registered file types. Highlight the JNLP file by selecting JNLP file under the Extensions column. 
• Click the Change button. 
• From the Open With window, click the Browse button. 
• From the Open With dialogue window, locate the file javaws.exe: 
• In the C:\Program Files folder, double click the Java folder 
• Double click the jre* folder 
• Double click the bin folder 
• Select the javaws.exe application 
• Click the Open button 
• Click the OK button to close the Open With window. 
• Click the Apply button to apply settings to the Folder Options window. Click the OK button to close the Folder Options window. 
• JNLP files will now open, by default, with Java Web Start

Src:
https://www.nhdeeds.org/wp-content/uploads/2020/02/HowToSetWindowsFileAssociationsToOpenJNLPFiles.html