Collections: Queue's offer/poll/peek return null instead of throwing

Queue has two parallel method families: add/remove/element throw on failure, while offer/poll/peek report failure by returning false or null, which suits code that expects an empty queue as a normal case.

Code

Queue<String> q = new LinkedList<>();
System.out.println("poll on empty: " + q.poll());
System.out.println("peek on empty: " + q.peek());
try {
    q.remove();
} catch (NoSuchElementException e) {
    System.out.println("remove on empty throws: " + e.getClass().getSimpleName());
}
q.offer("task-1");
System.out.println("element(): " + q.element());

Output

poll on empty: null
peek on empty: null
remove on empty throws: NoSuchElementException
element(): task-1