How to use aslist in Java

Function

1. Returns a fixed-size list supported by the specified array.

2. The ArrayList returned by this method is not our commonly used collection class java.util.ArrayList. ArrayList is the internal class java.util.Arrays.ArrayList of Arrays.

Example

private static class ArrayList<E> extends AbstractList<E>
        implements RandomAccess, java.io.Serializable
    {
        private static final long serialVersionUID = -2764017481108945198L;
        private final E[] a;
 
        ArrayList(E[] array) {
            a = Objects.requireNonNull(array);
        }
 
        @Override
        public int size() {
            return a.length;
        }
 
        @Override
        public Object[] toArray() {
            return a.clone();
        }
 
        @Override
        @SuppressWarnings("unchecked")
        public <T> T[] toArray(T[] a) {
            int size = size();
            if (a.length < size)
                return Arrays.copyOf(this.a, size,
                                     (Class<? extends T[]>) a.getClass());
            System.arraycopy(this.a, 0, a, 0, size);
            if (a.length > size)
                a[size] = null;
            return a;
        }
 
        @Override
        public E get(int index) {
            return a[index];
        }
 
        @Override
        public E set(int index, E element) {
            E oldValue = a[index];
            a[index] = element;
            return oldValue;
        }
 
        @Override
        public int indexOf(Object o) {
            E[] a = this.a;
            if (o == null) {
                for (int i = 0; i < a.length; i++)
                    if (a[i] == null)
                        return i;
            } else {
                for (int i = 0; i < a.length; i++)
                    if (o.equals(a[i]))
                        return i;
            }
            return -1;
        }
 
        @Override
        public boolean contains(Object o) {
            return indexOf(o) != -1;
        }
 
        @Override
        public Spliterator<E> spliterator() {
            return Spliterators.spliterator(a, Spliterator.ORDERED);
        }
 
        @Override
        public void forEach(Consumer<? super E> action) {
            Objects.requireNonNull(action);
            for (E e : a) {
                action.accept(e);
            }
        }
 
        @Override
        public void replaceAll(UnaryOperator<E> operator) {
            Objects.requireNonNull(operator);
            E[] a = this.a;
            for (int i = 0; i < a.length; i++) {
                a[i] = operator.apply(a[i]);
            }
        }
 
        @Override
        public void sort(Comparator<? super E> c) {
            Arrays.sort(a, c);
        }
    }

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