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Arrays.asList is a static generic method in java.util.Arrays that converts an array or a sequence of arguments into a java.util.List<T>. The returned list is a fixed-size, array-backed view of the original data, and it preserves the order of elements.

The list is backed by the array: changes to elements via the list reflect in the array and vice versa. Structural changes are not supported: you cannot add or remove elements from the list; attempting to do so throws UnsupportedOperationException. The list is not a java.util.ArrayList; it is an internal fixed-size list (often referred to as Arrays$ArrayList) with a fixed length equal to the underlying array or the number of arguments provided.

Common pitfalls relate to type and boxing, especially with primitive arrays. If you pass a primitive array such as int[] to Arrays.asList, you get a List<int[]> with a single element—the entire array—rather than a list of integers. To obtain a List<Integer>, either pass individual numbers (Arrays.asList(1, 2, 3)) or use a stream to box primitives (Arrays.stream(arr).boxed().collect(Collectors.toList())).

If a mutable list is needed, wrap the result in a new ArrayList: new ArrayList<>(Arrays.asList(...)). This creates a modifiable list independent of the backing array.

In modern Java, List.of provides an immutable alternative (Java 9+). It returns an unmodifiable list and shares no backing array, differing from Arrays.asList in mutability and backing semantics. For mutable collections based on an array, typical practice is to use a new ArrayList<>(Arrays.asList(...)).