Comments on: Convert ArrayList to Arrays in Java

By: Hauke

Hauke — Sat, 04 Jul 2009 15:24:44 +0000

If you use an array with the correct size within the toArray method, the result is returned within the provided array. If you use a “new T[0]” another array has to be created, that is thrown away after the type information is read.
So it is bad style to use “new T[0]“.

By: Dave

Dave — Fri, 03 Jul 2009 11:56:59 +0000

Thanks!
It was useful for me! :)

By: Moe Lavigne

Moe Lavigne — Fri, 03 Jul 2009 03:17:15 +0000

Maybe the following comment would have been better:

This is also works: T[] countries = list.toArray(new T[0]);

The \"toArray\" method automatically adjusts the size of the target array, but it must be initialized… I just use zero;

By: TinhTruong

TinhTruong — Fri, 03 Jul 2009 02:29:48 +0000

You don’t have to put the list.size() to the new array, just 0 is enough because it just uses the information about the type of the return array, not the size, so the following code will work:
T [] countries = list.toArray(new T[0]);

By: Moe Lavigne

Moe Lavigne — Fri, 03 Jul 2009 00:47:26 +0000

String[] countries = new String[0];

List list = new ArrayList();
list.add(“India”);
list.add(“Switzerland”);
list.add(“Italy”);
list.add(“France”);

countries = list.toArray(countries);