Spring Boot - Impossible for JavaFX app to implement SmartLifeCycle?

Question

I am building a JavaFX app and i want it to implement Spring's SmartLifeCycle interface to perform tasks when the main class terminates. A JavaFX main class must extend the Application class which contains a stop() method. The SmartLifeCycle interface also contains a stop method. It looks like these 2 methods refuse to co-exist even if they have different method signatures. The JavaFX method extended from the Application class has no parameters and throws an exception while the implemented method from SmartLifeCycle takes a Runnable object as an argument.

Is it possible for both these methods to exist in the same class? Both are required to implement by subclasses therefore the compiler complains no matter what i do.

Thanks

The 2 stop() methods originate from different sources though, one is from the JavaFX Application class and one from the Spring SmartLifeCycle interface. This is not method overloading but rather the compiler being confused on what i'm trying to do. I'm preparing a code example now. — Martin, May 21 '19 at 16:28
You are correct, i removed the throws Exception clause and the compiler is happy now. Please post an answer so I can accept it :). Thank you! — Martin, May 21 '19 at 16:36

score 1 · Accepted Answer · answered May 21 '19 at 16:44

The Application abstract class has the following method:

public void stop() throws Exception {}

And the SmartLifecycle interface has the following method, inherited from Lifecycle:

void stop();

As you can see, one can throw an Exception and the other cannot. If you want to extend Application and implement SmartLifecycle, then you can't have throws Exception in your overridden stop() method.

public class MySpringJavaFxApp extends Application implements SmartLifecycle {

    @Override
    public void start(Stage primaryStage) throws Exception {
        // ...
    }

    @Override
    public void stop() {
        // ...
    }

    // other methods that need to be implemented...
}

But note you have to override stop() to remove the throws clause. Otherwise the methods clash (Application#stop is not abstract, thus tries to implement Lifecycle#stop in this situation).

Spring Boot - Impossible for JavaFX app to implement SmartLifeCycle?

1 Answers1