1. What is ArrayList ? Junior A. a resizable array-backed List offering fast random access by index but slow insertion or removal in the middle B. a doubly-linked-node List that gives fast insertion and removal at the ends but slow index-based access C. a key-value structure backed by a red-black tree that keeps keys sorted in natural or comparator order with logarithmic lookup D. a hash-table-and-linked-list map that preserves insertion order of its keys during iteration
2. Which term means: "a resizable array-backed List offering fast random access by index but slow insertion or removal in the middle"? Junior A. HashSet B. HashMap C. ArrayList D. TreeMap
3. Which statement is correct? Junior A. ArrayList — a resizable array-backed List offering fast random access by index but slow insertion or removal in the middle B. ArrayList — a thread-safe map that allows concurrent reads and segmented writes without locking the entire structure C. ArrayList — a hash-table-and-linked-list map that preserves insertion order of its keys during iteration D. ArrayList — a collection backed by a hash map that stores only unique elements with no defined order
4. What is LinkedList ? Mid A. a key-value structure backed by a red-black tree that keeps keys sorted in natural or comparator order with logarithmic lookup B. a collection backed by a hash map that stores only unique elements with no defined order C. a doubly-linked-node List that gives fast insertion and removal at the ends but slow index-based access D. a thread-safe map that allows concurrent reads and segmented writes without locking the entire structure
5. Which term means: "a doubly-linked-node List that gives fast insertion and removal at the ends but slow index-based access"? Mid A. LinkedList B. LinkedHashMap C. ArrayList D. HashMap
6. Which statement is correct? Mid A. LinkedList — a collection backed by a hash map that stores only unique elements with no defined order B. LinkedList — a doubly-linked-node List that gives fast insertion and removal at the ends but slow index-based access C. LinkedList — a resizable array-backed List offering fast random access by index but slow insertion or removal in the middle D. LinkedList — a hash-table-and-linked-list map that preserves insertion order of its keys during iteration
7. What is HashMap ? Junior A. a thread-safe map that allows concurrent reads and segmented writes without locking the entire structure B. a key-value structure backed by a hash table giving average constant-time lookup with no guaranteed ordering of keys C. a resizable array-backed List offering fast random access by index but slow insertion or removal in the middle D. a collection backed by a hash map that stores only unique elements with no defined order
8. Which term means: "a key-value structure backed by a hash table giving average constant-time lookup with no guaranteed ordering of keys"? Junior A. TreeMap B. HashMap C. HashSet D. LinkedList
9. Which statement is correct? Junior A. HashMap — a resizable array-backed List offering fast random access by index but slow insertion or removal in the middle B. HashMap — a doubly-linked-node List that gives fast insertion and removal at the ends but slow index-based access C. HashMap — a collection backed by a hash map that stores only unique elements with no defined order D. HashMap — a key-value structure backed by a hash table giving average constant-time lookup with no guaranteed ordering of keys
10. What is TreeMap ? Mid A. a key-value structure backed by a hash table giving average constant-time lookup with no guaranteed ordering of keys B. a doubly-linked-node List that gives fast insertion and removal at the ends but slow index-based access C. a key-value structure backed by a red-black tree that keeps keys sorted in natural or comparator order with logarithmic lookup D. a resizable array-backed List offering fast random access by index but slow insertion or removal in the middle
11. Which term means: "a key-value structure backed by a red-black tree that keeps keys sorted in natural or comparator order with logarithmic lookup"? Mid A. LinkedHashMap B. ConcurrentHashMap C. TreeMap D. HashMap
12. Which statement is correct? Mid A. TreeMap — a resizable array-backed List offering fast random access by index but slow insertion or removal in the middle B. TreeMap — a key-value structure backed by a red-black tree that keeps keys sorted in natural or comparator order with logarithmic lookup C. TreeMap — a thread-safe map that allows concurrent reads and segmented writes without locking the entire structure D. TreeMap — a doubly-linked-node List that gives fast insertion and removal at the ends but slow index-based access
13. What is LinkedHashMap ? Mid A. a key-value structure backed by a red-black tree that keeps keys sorted in natural or comparator order with logarithmic lookup B. a collection backed by a hash map that stores only unique elements with no defined order C. a key-value structure backed by a hash table giving average constant-time lookup with no guaranteed ordering of keys D. a hash-table-and-linked-list map that preserves insertion order of its keys during iteration
14. Which term means: "a hash-table-and-linked-list map that preserves insertion order of its keys during iteration"? Mid A. ArrayList B. TreeMap C. HashSet D. LinkedHashMap
15. Which statement is correct? Mid A. LinkedHashMap — a hash-table-and-linked-list map that preserves insertion order of its keys during iteration B. LinkedHashMap — a doubly-linked-node List that gives fast insertion and removal at the ends but slow index-based access C. LinkedHashMap — a resizable array-backed List offering fast random access by index but slow insertion or removal in the middle D. LinkedHashMap — a collection backed by a hash map that stores only unique elements with no defined order
16. What is HashSet ? Mid A. a collection backed by a hash map that stores only unique elements with no defined order B. a key-value structure backed by a hash table giving average constant-time lookup with no guaranteed ordering of keys C. a doubly-linked-node List that gives fast insertion and removal at the ends but slow index-based access D. a key-value structure backed by a red-black tree that keeps keys sorted in natural or comparator order with logarithmic lookup
17. Which term means: "a collection backed by a hash map that stores only unique elements with no defined order"? Mid A. ConcurrentHashMap B. LinkedList C. LinkedHashMap D. HashSet
18. Which statement is correct? Mid A. HashSet — a key-value structure backed by a red-black tree that keeps keys sorted in natural or comparator order with logarithmic lookup B. HashSet — a doubly-linked-node List that gives fast insertion and removal at the ends but slow index-based access C. HashSet — a resizable array-backed List offering fast random access by index but slow insertion or removal in the middle D. HashSet — a collection backed by a hash map that stores only unique elements with no defined order
19. What is ConcurrentHashMap ? Senior A. a resizable array-backed List offering fast random access by index but slow insertion or removal in the middle B. a key-value structure backed by a red-black tree that keeps keys sorted in natural or comparator order with logarithmic lookup C. a key-value structure backed by a hash table giving average constant-time lookup with no guaranteed ordering of keys D. a thread-safe map that allows concurrent reads and segmented writes without locking the entire structure
20. Which term means: "a thread-safe map that allows concurrent reads and segmented writes without locking the entire structure"? Senior A. TreeMap B. LinkedList C. ArrayList D. ConcurrentHashMap
21. Which statement is correct? Senior A. ConcurrentHashMap — a key-value structure backed by a hash table giving average constant-time lookup with no guaranteed ordering of keys B. ConcurrentHashMap — a collection backed by a hash map that stores only unique elements with no defined order C. ConcurrentHashMap — a thread-safe map that allows concurrent reads and segmented writes without locking the entire structure D. ConcurrentHashMap — a hash-table-and-linked-list map that preserves insertion order of its keys during iteration