Java TreeSet MCQ Questions and Answers

Q. What is the data structure used to implement the LinkedTreeSet in Java?

Q. Which interface does LinkedTreeSet implement in Java?

Q. What is the time complexity of adding an element to a LinkedTreeSet in Java?

Q. What is the result of calling linkedTreeSet.add(10) if linkedTreeSet contains [5, 8, 15, 3]?

Q. How do you iterate over the elements in a LinkedTreeSet?

Q. What is the output of the following code snippet?
LinkedTreeSet<String> colors = new LinkedTreeSet<>(List.of("red", "green", "blue"));
colors.remove("green");
System.out.println(colors);

Q. What is the time complexity of checking if an element exists in a LinkedTreeSet?

Q. How do you create an empty LinkedTreeSet in Java?

Q. What is the result of calling linkedTreeSet.ceiling(8) if linkedTreeSet contains [5, 9, 12, 15]?

Q. What is the output of the following code snippet?
LinkedTreeSet<Integer> numbers = new LinkedTreeSet<>(List.of(1, 2, 3, 4, 5));
numbers.descendingSet().forEach(System.out::println);

Q. What will be the output of the following code?

TreeSet<String> treeSet = new TreeSet<>();
treeSet.add("Apple");
treeSet.add("Banana");
treeSet.add("Orange");
treeSet.add("Grapes");
for (String fruit : treeSet) {
System.out.print(fruit + " ");
}

Apple Banana Grapes Orange

Apple Banana Orange Grapes

Apple Orange Banana Grapes

Banana Apple Orange Grapes

Q. Which of the following statements about TreeSet is true?

TreeSet allows duplicate elements.

TreeSet does not allow null elements.

TreeSet maintains the insertion order of elements.

TreeSet is not sorted.

Q. How can you create a TreeSet that sorts elements based on their lengths (for strings) or numerical values (for numbers) in descending order?

TreeSet<String> treeSet = new TreeSet<>((a, b) -> b.length() - a.length());

TreeSet<String> treeSet = new TreeSet<>(Comparator.comparing(String::length).reversed());

TreeSet<String> treeSet = new TreeSet<>(Collections.reverseOrder());

TreeSet<String> treeSet = new TreeSet<>((a, b) -> a.compareTo(b));

Q. What will be the output of the following code?

TreeSet<Integer> treeSet = new TreeSet<>();
treeSet.add(3);
treeSet.add(1);
treeSet.add(4);
treeSet.add(2);
for (int num : treeSet) {
System.out.print(num + " ");
}

1 2 3 4

3 4 2 1

3 1 4 2

4 3 2 1

Q. How can you remove a specific element from a TreeSet?

treeSet.remove(element);

treeSet.delete(element);

treeSet.removeElement(element);

treeSet.clear();

Q. What will be the output of the following code?

TreeSet<String> treeSet = new TreeSet<>();
treeSet.add("Apple");
treeSet.add("apple");
for (String fruit : treeSet) {
System.out.print(fruit + " ");
}

Apple

Apple apple

apple Apple

Error: Duplicate element

Q. How can you create a TreeSet that contains custom objects and sorts them based on a specific property?

TreeSet<MyClass> treeSet = new TreeSet<>(Comparator.comparing(MyClass::getProperty));

TreeSet<MyClass> treeSet = new TreeSet<>();

TreeSet<MyClass> treeSet = new TreeSet<>((a, b) -> a.getProperty().compareTo(b.getProperty()));

TreeSet<MyClass> treeSet = new TreeSet<>((a, b) -> b.getProperty().compareTo(a.getProperty()));

Q. What will be the output of the following code?

TreeSet<Integer> treeSet = new TreeSet<>();
treeSet.add(5);
treeSet.add(2);
treeSet.add(8);
treeSet.add(1);
System.out.println(treeSet.first());
System.out.println(treeSet.last());

1
8

5
8

2
5

1
5

Q. How can you check if a TreeSet is empty?

if (treeSet.isEmpty()) {...}

if (treeSet.size() == 0) {...}

if (!treeSet.contains(null)) {...}

if (treeSet.first() == null) {...}

Q. What will be the output of the following code?

TreeSet<String> treeSet = new TreeSet<>();
treeSet.add("Cherry");
treeSet.add("Apple");
treeSet.add("Banana");
System.out.println(treeSet.lower("Apple"));
System.out.println(treeSet.higher("Apple"));

Banana
Cherry

null
Cherry

Banana
null

Apple
Cherry