make arrayList.toArray() return more specific types

Like this:

List<String> list = new ArrayList<String>();String[] a = list.toArray(new String[0]);

Before Java6 it was recommended to write:

String[] a = list.toArray(new String[list.size()]);

because the internal implementation would realloc a properly sized array anyway so you were better doing it upfront. Since Java6 the empty array is preferred, see .toArray(new MyClass[0]) or .toArray(new MyClass[myList.size()])?

If your list is not properly typed you need to do a cast before calling toArray. Like this:

    List l = new ArrayList<String>();    String[] a = ((List<String>)l).toArray(new String[l.size()]);

It doesn't really need to return Object[], for example:-

    List<Custom> list = new ArrayList<Custom>();    list.add(new Custom(1));    list.add(new Custom(2));    Custom[] customs = new Custom[list.size()];    list.toArray(customs);    for (Custom custom : customs) {        System.out.println(custom);    }

Here's my Custom class:-

public class Custom {    private int i;    public Custom(int i) {        this.i = i;    }    @Override    public String toString() {        return String.valueOf(i);    }}

arrayList.toArray(new Custom[0]);

http://download.oracle.com/javase/7/docs/api/java/util/ArrayList.html#toArray%28java.lang.Object[]%29