How do I determine the correct path for FXML files CSS files Images and other resources needed by my JavaFX Application

Question

My JavaFX programme must be able to locate FXML files, as well as stylesheets (CSS files) and images, in order to load them with the FXMLLoader. When I try to load these, I frequently receive errors or the item I'm trying to load doesn't load at all.

The error message I see for FXML files includes the following:

Caused by: java.lang.NullPointerException: location is not set

For images, the stack trace includes

Caused by: java.lang.IllegalArgumentException: Invalid URL: Invalid URL or resource not found

What is the best way for me to determine the correct resource path for these resources?

Answer 1

• Use the getClass method (). SomeOtherClass.class or getResource(...) getResource(...) to generate a resource URL
• To the getResource(...) method, pass either an absolute path (with a leading /) or a relative path (without a leading /). The path is the name of the package that contains the resource, with. replaced by /.
• In the resource route, do not use.. This will not work if the application is packaged as a jar file. Use an absolute path if the resource is not in the same package or a subpackage of the class.
• For FXML files, pass the URL directly to the FXMLLoader.
• Call toExternalForm() on the URL to generate the String to send to the Image or ImageView constructors, or to add to the stylesheets list.
• To troubleshoot, examine the content of your build folder (or jar file), not your source folde