Array to Collection: Optimized code

Is there a better way of achieving this?

public static List<String> toList(String[] array) {

    List<String> list = new ArrayList(array.length);

    for(int i=0; i<array.length; i++)
        list.add(array[i]);

    return list;
}

NOTE: Arrays.asList(a) Returns a fixed-size list backed by the specified array. (Changes to the returned list "write through" to the array.). I don't want that behavior. I assume that MY function above bypasses that (or am I wrong?)

So, here we have the alternative method:

public static List<String> toList(String[] array) {

    List<String> list = new ArrayList(array.length);

    list.addAll(Arrays.asList(array));

    return list;
}

Just looking at it, I don't believe it's FASTER than the first method.

What do you mean by better way:

more readable:

List<String> list = new ArrayList<String>(Arrays.asList(array));

less memory consumption, and maybe faster (but definitely not thread safe):

public static List<String> toList(String[] array) {
    if (array==null) {
       return new ArrayList(0);
    } else {
       int size = array.length;
       List<String> list = new ArrayList(size);
       for(int i = 0; i < size; i++) {
          list.add(array[i]);
       }
       return list;
    }
}

Btw: here is a bug in your first example:

array.length will raise a null pointer exception if array is null, so the check if (array!=null) must be done first.

Arrays.asList(array);

Example:

 List<String> stooges = Arrays.asList("Larry", "Moe", "Curly");

See Arrays.asList class documentation.

Arrays.asList(array)

Arrays uses new ArrayList(array). But this is not the java.util.ArrayList. It's very similar though. Note that this constructor takes the array and places it as the backing array of the list. So it is O(1).

In case you already have the list created, Collections.addAll(list, array), but that's less efficient.

Update: Thus your Collections.addAll(list, array) becomes a good option. A wrapper of it is guava's Lists.newArrayList(array).

Another way to do it:

Collections.addAll(collectionInstance,array);

What about :

List myList = new ArrayList(); 
String[] myStringArray = new String[] {"Java", "is", "Cool"}; 

Collections.addAll(myList, myStringArray);

Array to Collection: Optimized code

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