IllegalArgumentException when loading controller from FXML

Question

So I\'m coding this chat-client for a school project, and now I need to implement a GUI, using JavaFX. I\'ve built a neat looking GUI in Scene Builder. Whenever the client r

Answer 1

The syntax url="@..." in your FXML file refers to a path relative to the current FXMLLoader's location property.

However, when you load the FXML file, you are not providing the FXMLLoader with a location, but an input stream. Thus the location is null and (as seen in the stack trace), your path gets interpreted as

null/../../../../img/jim.png

To fix this, provide the location to the FXMLLoader, instead of the input stream:

try {
    FXMLLoader loader = new FXMLLoader(getClass().getResource("ChatForm.fxml"));
    Pane p = loader.load();
    ChatForm chatForm = (ChatForm) loader.getController();
    chatForm.test();
} catch (IOException e) {
    e.printStackTrace();
}

This will fix the immediate problem, assuming the path is actually correct. I think you still have other, essentially unrelated, problems, as you never seem to do anything with the scene graph you load (i.e. you never display the pane p).