toArray() question

[Charith Fernando]

hi,

i have seen code segments which uses the toArray() in different ways... just want to know the best mechanism and the difference...

(1)

   
List list = new ArrayList()
String[] array = (String[])list.toArrray(new String[0]);
 
 

(2)

   
List list = new ArrayList()
String[] array = (String[])list.toArrray(new String[list.size()]);
 
 

please note that this is in Java 1.4 in Java 5 we dont need the cast if we have a list which will only contain Strings...


Thank you
Charith

[wise owen]

//ArrayList.java
  public Object[] toArray(Object[] a)
  {
    if (a.length < size)
      a = (Object[]) Array.newInstance(a.getClass().getComponentType(),
                                       size);
    else if (a.length > size)
      a[size] = null;
    System.arraycopy(data, 0, a, 0, size);
    return a;
  }

If the passed array is large enough to contain the values to be returned, the method returns the passed array reference (that now contains the values to be returned) and not a newly created one.
[ October 23, 2006: Message edited by: wise owen ]