How to call a Java method with varargs from Scala.

Java varargs from Scala

I ran into the "ambiguous reference to overloaded definition" error while trying to create a Vaadin ShortcutAction from Scala like this:

    val upAction = new ShortcutAction("up", ShortcutAction.KeyCode.ARROW_UP, null)

ShortcutAction has a few constructors with repeating parameters (varargs), but specifying null as the last parameter clears things up in Java. Scala on the other hand seems unable to figure out which constructor I'm trying to call.

Now, Scala has a special syntax to tell the compiler to pass a Seq as varargs, ": _*". So, I figured out this would work:

    val upAction = new ShortcutAction("up", ShortcutAction.KeyCode.ARROW_UP, Array(): _*)

But I get the same error as before. So, what about trying to pass null as varargs?

    val upAction = new ShortcutAction("up", ShortcutAction.KeyCode.ARROW_UP, null: _*)

This actually crashes the Scala compiler (2.10.2) by failing an assertion. In the end I just created a simple wrapper class in Java:

  public class MyShortcutAction extends ShortcutAction {
	  public MyShortcutAction(String caption, int keyCode) {
		  super(caption, keyCode, null);
	  }

	  public MyShortcutAction(String caption, int keyCode, int modifier) {
		  super(caption, keyCode, new int[] { modifier });
	  }
  }
  
This works from Scala with no problems.

Funciona correctamente en scala 2.11.1 también.
Muchas Gracias!