How can I read a String[] from a JavaScriptObject? (GWT)

I am creating an object from JSON that has a String[] property, so the JSON looks like this:

{
key1: "val1", 
key2: ["val2a", "val2b", "val2c"],
}

What's the best way to define this as a JavaScriptObject?

Right now I am defining a new object JSString, so the java object looks like this:

public class MyObject extends JavaScriptObject {
   ...
   public JSArray<JSString> getKey2() {...    
}

This is kinda annoying. It'd be nice if I could do this:

public class MyObject extends JavaScriptObject {
   ...
   public String[] getKey2() {...    
}

But that doesn't work. Is there a better way? Thanks in advance