Practice 70 Java Collection Programming Questions

Practice 70 Java Collection Programming Questions

Q1. Write a Java program to demonstrate the use of ArrayList.
  - Input: Add(10), Add(20), Remove(10)
  - Expected Output: [20]

Q2. Write a Java program to find the size of an ArrayList.
  - Input: Add(10), Add(20)
  - Expected Output: 2

Q3. Write a Java program to add elements to a LinkedList and print them.
  - Input: Add(10), Add(20), Add(30)
  - Expected Output: [10, 20, 30]

Q4. Write a Java program to remove the first element of a LinkedList.
  - Input: Add(10), Add(20), RemoveFirst()
  - Expected Output: [20]

Q5. Write a Java program to remove the last element of a LinkedList.
  - Input: Add(10), Add(20), RemoveLast()
  - Expected Output: [10]

Q6. Write a Java program to demonstrate the use of HashSet.
  - Input: Add(10), Add(20), Add(20)
  - Expected Output: [10, 20]

Q7. Write a Java program to check if a HashSet contains a specific element.
  - Input: Add(10), Add(20), Contains(10)
  - Expected Output: True

Q8. Write a Java program to remove an element from a HashSet.
  - Input: Add(10), Add(20), Remove(10)
  - Expected Output: [20]

Q9. Write a Java program to demonstrate the use of TreeSet.
  - Input: Add(10), Add(20), Add(5)
  - Expected Output: [5, 10, 20]

Q10. Write a Java program to check if a TreeSet is empty.
   - Input: Add(10), Add(20), IsEmpty()
   - Expected Output: False

Q11. Write a Java program to demonstrate the use of HashMap.
   - Input: Put("a", 10), Put("b", 20)
   - Expected Output: {a=10, b=20}

Q12. Write a Java program to get a value from a HashMap.
   - Input: Put("a", 10), Get("a")
   - Expected Output: 10

Q13. Write a Java program to remove a key-value pair from a HashMap.
   - Input: Put("a", 10), Remove("a")
   - Expected Output: {}

Q14. Write a Java program to check if a HashMap contains a specific key.
   - Input: Put("a", 10), ContainsKey("a")
   - Expected Output: True

Q15. Write a Java program to demonstrate the use of TreeMap.
   - Input: Put("a", 10), Put("b", 20)
   - Expected Output: {a=10, b=20}

Q16. Write a Java program to check if a TreeMap contains a specific value.
   - Input: Put("a", 10), ContainsValue(10)
   - Expected Output: True

Q17. Write a Java program to iterate over the elements of a HashSet.
   - Input: Add(10), Add(20), Add(30)
   - Expected Output: 10 20 30

Q18. Write a Java program to iterate over the elements of an ArrayList.
   - Input: Add(10), Add(20), Add(30)
   - Expected Output: 10 20 30

Q19. Write a Java program to check if a List contains a specific element.
   - Input: Add(10), Add(20), Contains(20)
   - Expected Output: True

Q20. Write a Java program to reverse the elements of an ArrayList.
   - Input: Add(10), Add(20), Add(30)
   - Expected Output: [30, 20, 10]

Q21. Write a Java program to clear all elements from a LinkedList.
   - Input: Add(10), Add(20), Clear()
   - Expected Output: []

Q22. Write a Java program to add an element at a specific position in a List.
   - Input: Add(10), Add(20), Add(1, 15)
   - Expected Output: [10, 15, 20]

Q23. Write a Java program to convert a List to an Array.
   - Input: Add(10), Add(20), ToArray()
   - Expected Output: [10, 20]

Q24. Write a Java program to create a sublist from an ArrayList.
   - Input: Add(10), Add(20), Add(30), Sublist(0, 2)
   - Expected Output: [10, 20]

Q25. Write a Java program to demonstrate the use of PriorityQueue.
   - Input: Add(10), Add(20), Add(15)
   - Expected Output: [10, 15, 20]

Q26. Write a Java program to poll (remove) an element from a PriorityQueue.
   - Input: Add(10), Add(20), Poll()
   - Expected Output: 10

Q27. Write a Java program to add all elements of one List to another List.
   - Input: Add(10), Add(20), AddAll([30, 40])
   - Expected Output: [10, 20, 30, 40]

Q28. Write a Java program to check if a List is empty.
   - Input: Add(10), IsEmpty()
   - Expected Output: False

Q29. Write a Java program to create a List from an array.
   - Input: Array([10, 20, 30])
   - Expected Output: [10, 20, 30]

Q30. Write a Java program to add a collection to a List.
   - Input: Add(10), Add(20), AddAll([30, 40])
   - Expected Output: [10, 20, 30, 40]

Q31. Write a Java program to find the common elements between two sets.
   - Input: Set1([10, 20, 30]), Set2([20, 30, 40])
   - Expected Output: [20, 30]

Q32. Write a Java program to merge two lists.
   - Input: List1([10, 20]), List2([30, 40])
   - Expected Output: [10, 20, 30, 40]

Q33. Write a Java program to remove all elements from one List that are present in another List.
   - Input: List1([10, 20, 30]), List2([20])
   - Expected Output: [10, 30]

Q34. Write a Java program to find the index of an element in an ArrayList.
   - Input: Add(10), Add(20), IndexOf(20)
   - Expected Output: 1

Q35. Write a Java program to find the first and last occurrence of an element in a List.
   - Input: Add(10), Add(20), Add(10), IndexOf(10), LastIndexOf(10)
   - Expected Output: 0, 2

Q36. Write a Java program to add an element at the beginning of a LinkedList.
   - Input: Add(10), AddFirst(5)
   - Expected Output: [5, 10]

Q37. Write a Java program to find the sum of all elements in a List of Integers.
   - Input: Add(10), Add(20), Add(30)
   - Expected Output: 60

Q38. Write a Java program to create a HashSet and remove a specific element.
   - Input: Add(10), Add(20), Remove(10)
   - Expected Output: [20]

Q39. Write a Java program to check if a Map contains a specific value.
   - Input: Put("a", 10), Put("b", 20), ContainsValue(20)
   - Expected Output: True

Q40. Write a Java program to find the keys in a HashMap.
   - Input: Put("a", 10), Put("b", 20)
   - Expected Output: [a, b]

Q41. Write a Java program to find the values in a HashMap.
   - Input: Put("a", 10), Put("b", 20)
   - Expected Output: [10, 20]

Q42. Write a Java program to clone a HashMap.
   - Input: Put("a", 10), Put("b", 20)
   - Expected Output: {a=10, b=20}

Q43. Write a Java program to merge two HashMaps.
   - Input: Map1({a=10}), Map2({b=20})
   - Expected Output: {a=10, b=20}

Q44. Write a Java program to find the entry set of a HashMap.
   - Input: Put("a", 10), Put("b", 20)
   - Expected Output: [(a=10), (b=20)]

Q45. Write a Java program to sort a HashMap by keys.
   - Input: Put("c", 30), Put("a", 10), Put("b", 20)
   - Expected Output: {a=10, b=20, c=30}

Q46. Write a Java program to sort a HashMap by values.
   - Input: Put("a", 30), Put("b", 10), Put("c", 20)
   - Expected Output: {b=10, c=20, a=30}

Q47. Write a Java program to demonstrate the use of ArrayDeque.
   - Input: AddFirst(10), AddLast(20), RemoveFirst()
   - Expected Output: [20]

Q48. Write a Java program to check if a LinkedList contains an element.
   - Input: Add(10), Add(20), Contains(20)
   - Expected Output: True

Q49. Write a Java program to compare two ArrayLists.
   - Input: List1([10, 20]), List2([10, 20])
   - Expected Output: True

Q50. Write a Java program to find the maximum element in a List of Integers.
   - Input: Add(10), Add(20), Add(30)
   - Expected Output: 30

Q51. Write a Java program to shuffle elements of a List.
   - Input: Add(10), Add(20), Add(30)
   - Expected Output: Random order of elements

Q52. Write a Java program to convert a List to a Set.
   - Input: Add(10), Add(20), Add(20)
   - Expected Output: [10, 20]

Q53. Write a Java program to perform union of two sets.
   - Input: Set1([10, 20]), Set2([20, 30])
   - Expected Output: [10, 20, 30]

Q54. Write a Java program to perform intersection of two sets.
   - Input: Set1([10, 20]), Set2([20, 30])
   - Expected Output: [20]

Q55. Write a Java program to remove all elements from a HashSet that are not in another HashSet.
   - Input: Set1([10, 20, 30]), Set2([20, 30])
   - Expected Output: [20, 30]

Q56. Write a Java program to find the difference between two sets.
   - Input: Set1([10, 20, 30]), Set2([20, 30])
   - Expected Output: [10]

Q57. Write a Java program to find the first element in a List.
   - Input: Add(10), Add(20)
   - Expected Output: 10

Q58. Write a Java program to check if a list is a sublist of another list.
   - Input: List1([10, 20]), List2([10])
   - Expected Output: True

Q59. Write a Java program to create an empty ArrayList and add elements to it.
   - Input: Add(10), Add(20)
   - Expected Output: [10, 20]

Q60. Write a Java program to remove elements from a List by index.
   - Input: Add(10), Add(20), Remove(0)
   - Expected Output: [20]

Q61. Write a Java program to check if a LinkedList is a palindrome.
   - Input: Add(10), Add(20), Add(10)
   - Expected Output: True

Q62. Write a Java program to concatenate two Lists.
   - Input: List1([10, 20]), List2([30, 40])
   - Expected Output: [10, 20, 30, 40]

Q63. Write a Java program to find the first and last elements in a List.
   - Input: Add(10), Add(20)
   - Expected Output: 10, 20

Q64. Write a Java program to remove elements in a List by value.
   - Input: Add(10), Add(20), Remove(10)
   - Expected Output: [20]

Q65. Write a Java program to count the frequency of each element in a List.
   - Input: Add(10), Add(20), Add(10)
   - Expected Output: 10 -> 2, 20 -> 1

Q66. Write a Java program to create a LinkedHashSet and demonstrate its functionality.
   - Input: Add(10), Add(20)
   - Expected Output: [10, 20]

Q67. Write a Java program to compare two sets.
   - Input: Set1([10, 20]), Set2([10, 20])
   - Expected Output: True

Q68. Write a Java program to find the union of two Lists.
   - Input: List1([10, 20]), List2([30, 40])
   - Expected Output: [10, 20, 30, 40]

Q69. Write a Java program to convert a Set to a List.
   - Input: Set([10, 20, 30])
   - Expected Output: [10, 20, 30]

Q70. Write a Java program to find the first element in a HashSet.
   - Input: Add(10), Add(20)
   - Expected Output: 10