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What is the cost of using Arrays.asList to convert static object arrays? Assuming that the object array has N items is it just an O(N) algorithm, where all of the items are copied by reference or is it merely a facade where the original array is put behind a List facade?
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The asList() method of java. util. Arrays class is used to return a fixed-size list backed by the specified array. This method acts as a bridge between array-based and collection-based APIs, in combination with Collection.
How is Arrays. asList() different than the standard way of initialising List? Explanation: List returned by Arrays. asList() is a fixed length list which doesn't allow us to add or remove element from it.
Only this list is a view of the original list, so it can change if you change the original list. Arrays. asList is not completely immutable, it does not have a restriction on set . Similarly, changing the backing array (if you hold it) will change the list.
asList returns a fixed-size list that is backed by the specified array; the returned list is serializable and allows random access.
It is cheap, O(1). As you suspect the list is merely a wrapper around the array. This is confirmed by the Java API documentation:
Returns a fixed-size list backed by the specified array. (Changes to the returned list "write through" to the array.)
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