How to Duplicate an array list in Java? [duplicate]

You can create a copy of the old ArrayList with:

List<Movie> newList = new ArrayList<Movie>(oldList);

You should know that this creates a shallow copy of the original ArrayList, so all of the objects in both lists will be the same, but the two lists will be different objects.

Though the question is ambiguous, you can use

List<Integer> newList = new ArrayList<Integer>(oldList); to copy an old List

and

Arrays.copyOf() to copy array.

System.arraycopy()

public static void arraycopy(Object src, int srcPos, Object dest, int destPos, int length)

Source

You can get Array from original Array List as below:

Movie movieArray[] = arrayListMovie
    .toArray(new Movie[arrayListMovie.size()]);

Every Collection Class provide a constructor to crate a duplicate collection Object.

List<Movie> newList = new ArrayList<Movie>(oldList);

since newList and oldList are different object so you can also create a clone of this object-

public static List<Movie> cloneList(List<Movie> oldList) {
    List<Movie> clonedList = new ArrayList<Movie>(oldList.size());
    for (Movie movie: oldList) {
        clonedList.add(new Movie(movie));
    }
    return clonedList;
}

ArrayList is also dynamic array,but if you want to store this in array you can do this as-

int n=oldList.size();
Movie[] copiedArray=new Movie[n];

for (int i=0;i<oldList.size();i++){
copiedArray[i]=oldList.get(i);
}