How come fruit.toArray(new String[0]); creates a new filled array of 3 elements?

He mentions the syntax is super-weird, and it's because of the way that toArray() works.

Here's the Collections.toArray() documentation, which is kind of obtuse, because that's how documentation gets the closer you get to the bare metal of the operating system/system architecture :)

fruit.toArray(new String[0]);

So, the toArray() function that all Collections must have returns an Object array (Object[])

Objects (like, the actual Object Object, the Top Type, the Thing Which All Others Subclass) can't be downcast to anything else, because they're.... not anything else. :)

Since you want to have an array of Strings, they graciously overloaded toArray to accept a parameter, and that's the type of array you want it to be. That parameter (argument) is a new array of the type you want. In this case, a String array.

So look at each part separately...

String[] someWords;   // that creates a reference to a String array, not an array itself, right?

String[] neededArrayType = new String[0];  // that creates a new String array of the type I want

someWords = someCollection.toArray(neededArrayType);

So what we're doing is setting up the variable to "hold" the array (someWords) and then calling someCollection's .toArray() method. We're feeding it the array we want to store it in (neededArrayType) but if it's not the right size, it'll create a new one of the right type for us so the collection can plug all of its values into it.