Invoking JavaFX functions that don't exist

What happens when you try to execute the following Java code fragment?

String s = null;
System.out.println (s.length ());

It's not hard to figure out that a NullPointerException object is thrown. You cannot invoke a method via the null reference.

However, you can get away with something similar in JavaFX Script, which the following code fragment demonstrates:

var x: function (): Void;
println (x); // Output: null
x ();
x = null;
x ();
x = function (): Void { println ("x() invoked") }
x () // Output: x() invoked

The code fragment initially creates variable x of type function (): Void. Furthermore, this variable is initialized to null, which the subsequent println (x); expression proves.

Notice the first x (); invocation. You might expect that the JavaFX runtime would throw a NullPointerException, but this doesn't happen. In fact, the invocation is ignored.

To make this more explicit, the code fragment assigns null to x and once more executes x ();. Same result.

Finally, the code fragment assigns an anonymous function to x and executes x (), which results in the function being invoked and outputting x() invoked.

This "ignore a function invocation when the function variable contains null" behavior is present in JavaFX 1.0 and 1.1, and appears to be a useful feature for making code more robust. However, it can also mask bugs when a function must be executed but never is because its function variable contains null.

Do you think that a NullPointerException should be thrown in this situation, or is the ignore behavior okay with you?