Question

Same idea as my previous question, just a little more advanced. I want to write the following Scala code in Java:

Option(System.getProperty("not.present")).orElse(Some("default")).get

I tried this:

    final Function0<Option<String>> elseOption = new Function0<Option<String>>() { 
        @Override public Option<String> apply() { 
            return new Some<String>("default"); 
        }
    };

    final Option<String> notPresent =
        new Some<String>(System.getProperty("not.present")).
        orElse(elseOption).get();

But I get:

<anonymous OptionDemo$1> is not abstract and does not override abstract method apply$mcD$sp() in scala.Function0
[error]       orElse(new Function0<Option<String>>() {

Answer 1

Extend AbstractFunction0 instead of Function0. That should give you the trait-provided methods.