How to Remove File Association Windows 10
To remove file type association in Windows 10, you can go to modify Windows Registry. Here is a simple guide and you can refer to it to remove file type association of the file extension you want.

1. Press Windows + R to open Run window.
2. Input regedit and click OK button to launch Registry Editor.
3. Copy-paste the following path to the address bar and press Enter: Computer\HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts.
4. Under FileExts key, find the file extension you want to remove file association for.
5. Right click on the FileExtension on the left side of the screen, choose Export. Save as something like "file ext java.reg" (use the .reg extension).
6. Right-click the file extension on the left side of the screen and choose Delete.
7. To reverse the delete, double-click the file you saved.