Java Quize Questions

Q.1 A Queue implements First-In-First-Out(FIFO) data structrure.Which method removes the first element of a list? 1. queue.remove 2. queue.get 3. queue.poll 4. queue.dequeue Ans :- queue.poll Q.2 Collections in Java are an extension of what class? 1.Util 2.Iterable 3.Correct 4.List 5.Interface Ans:- Iterable Q.3 What is a characteristic of an ArrayList? 1.It is faster at removing elements from the middle of a list. 2.It takes up less memory than a linked list. 3.It is harder to implement than a linked list. 4.It is slower at retrieving elements at a particular location. Ans:- It takes up less memory than a linked list. Q.4 What prints to the console after this code executes? LinkedList myList = new LinkedList(); myList.add("A"); myList.add("C"); myList.add(2, "B"); myList.remove("B"); System.out.println(myList); 1. [A, C] 2.[C, A] 3.[A] 4.[C] Ans :- 1. [A, C] Q.5 You create a HashMap data structure using the following statement. What is the correct way to add a new element? HashMap datebook = new HashMap<>(); 1.datebook.put("Mary", 20210405); 2.datebook.set("Mary", 20210405); 3.datebook.add("Mary", 20210405); 4.datebook.insert("Mary", 20210405); Ans :- 1.datebook.put("Mary", 20210405); Q.6 What are you guaranteed when you use a LinkedHashMap as opposed to a HashMap? 1.The order in which the elements were inserted is preserved. 2.The order of the elements is sorted by the datatype. 3.The order is maintained like a stack. 4.The order of the elements is sorted by the frequency in which they are accessed. Ans:- The order in which the elements were inserted is preserved. Q.7 You want to create a list that is capable of returning the last element that was accessed. What is the correct declaration statement to accomplish this? 1.LinkedHashMap logbook = new LinkedHashMap(false, 0.75f, 4); 2.LinkedHashMap logbook = new LinkedHashMap(4, 0.75f, false); 3.LinkedHashMap logbook = new LinkedHashMap(4, 0.75f, true); 4.LinkedHashMap logbook = new LinkedHashMap(true, 0.75f, 4); Ans:- LinkedHashMap logbook = new LinkedHashMap(4, 0.75f, true); Q.8