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Collections Framework

25 Topics
1

Collections Framework Overview

Analyze the Java Collections Framework architecture, distinguishing legacy structures from modern standard interfaces.

Focuses on hierarchy root interfaces (Collection, Map), legacy class problems (Vector, Hashtable), and structural benefits.
2

Collection Interface

Analyze the root Collection interface contracts, including bulk, mutation, and stream operations.

Focuses on methods present in Collection, iterator factory contract, and bulk operations like retainAll/containsAll.
3

List Interface

Analyze the List interface contracts, positional indexing operations, duplicates handling, and the ListIterator interface.

Focuses on ordered structures, index-based access exceptions, ListIterator bidirectional cursor movements, and subList structural changes.
4

ArrayList

Analyze ArrayList internal structures, array copy mechanics, resizing logic, and random access execution.

Focuses on array growth factor (1.5x), System.arraycopy usage, O(1) indexing, and initial capacity optimization.
5

LinkedList

Analyze LinkedList doubly-linked node architecture, linear access costs, and its Deque interface functionality.

Focuses on Node heap overhead, O(1) inserts at boundaries, and comparison with ArrayList random access costs.
6

Vector

Analyze Vector legacy synchronized structures, expansion rules, and comparison to ArrayList.

Focuses on method level synchronization, 2x expansion factor, and thread safety overhead comparison.
7

Stack

Analyze the Stack legacy LIFO implementation, its inheritance issues, and modern Deque alternatives.

Focuses on why Stack extends Vector, Vector-to-Stack inheritance violations, and Deque stack operations.
8

Set Interface

Analyze the Set interface contract, duplicate prevention invariants, and algebraic set operations.

Focuses on mathematical set operations, duplicate rejection behavior, and comparisons with List.
9

HashSet

Analyze HashSet internal HashMap design, hashing distribution dependency, and constant lookup mechanisms.

Focuses on HashSet backing HashMap, PRESENT dummy object usage, O(1) performance limits, and null allowances.
10

LinkedHashSet

Analyze LinkedHashSet structures, insertion-order tracking via doubly-linked links, and memory overheads.

Focuses on doubly-linked lists linked through HashMap nodes, insertion-order preservation, and memory trade-offs.
11

TreeSet

Analyze TreeSet sorted structures, TreeMap backing, Red-Black tree navigation, and sorted complexity bounds.

Focuses on TreeSet backing TreeMap, Red-Black tree O(log N) complexity, sorted contracts, and Comparator usage.
12

Queue Interface

Analyze the Queue interface contract, FIFO structures, and comparing exit options (exception throwing vs value return).

Focuses on FIFO logic, comparison of offer/poll/peek vs add/remove/element, and Queue implementations.
13

PriorityQueue

Analyze PriorityQueue structures, binary heap array representations, and priority ordering.

Focuses on binary heap properties, O(log N) insert/delete, O(1) peek, and Comparable/Comparator usage.
14

Deque Interface

Analyze the Deque interface double-ended queue capabilities, stack/queue mappings, and implementations.

Focuses on LIFO/FIFO method mappings, comparison of ArrayDeque vs LinkedList, and stack replacement methods.
15

ArrayDeque

Analyze ArrayDeque circular array implementation, O(1) time bounds, and memory efficiencies.

Focuses on circular head/tail pointers, amortized O(1) complexities, null rejections, and memory efficiency.
16

Map Interface

Analyze the Map interface contract, key-value mappings, and collection view operations.

Focuses on key uniqueness, map collection views (keySet, values, entrySet), and null key/value behaviors.
17

HashMap

Analyze HashMap internal mechanics, bucket indexing, hash collision treeification, and resizing concurrency hazards.

Focuses on hashing algorithm, bucket layouts, collision trees (threshold 8), load factors, and resizing thread safety.
18

LinkedHashMap

Analyze LinkedHashMap structures, iteration order preservation, and building LRU caches.

Focuses on LinkedHashMap entry layouts, insertion vs access order, and LRU cache construction using removeEldestEntry.
19

TreeMap

Analyze TreeMap sorted key structures, Red-Black balancing trees, and NavigableMap range operations.

Focuses on Red-Black tree properties, O(log N) runtime bounds, Comparable key requirements, and range methods.
20

Hashtable

Analyze Hashtable legacy synchronized map design, method structures, and null exclusions.

Focuses on method-level synchronization overhead, null key/value rejection, and replacement with ConcurrentHashMap.
21

Comparable Interface

Analyze the Comparable interface natural sorting contract, compareTo implementation, and output constants.

Focuses on compareTo return values (-1, 0, 1), defining natural ordering, and natural sort integration.
22

Comparator Interface

Analyze the Comparator interface custom sorting contracts, functional structures, and chaining utilities.

Focuses on comparing compare vs compareTo, functional interface lambdas, and chaining comparator methods.
23

Iterator

Analyze Iterator traversal cursors, safe structural mutations, and fail-fast exception states.

Focuses on Iterator remove contracts, fail-fast checks (modCount), and ConcurrentModificationException mechanics.
24

Collections Class

Analyze Collections static utility methods, polymorphic algorithms, and wrapper decorators.

Focuses on distinguish Collection vs Collections, read-only wrapper limits, and synchronized wrappers.
25

Concurrent Collections

Analyze java.util.concurrent structures, ConcurrentHashMap segment evolution, and thread safety mechanisms.

Focuses on ConcurrentHashMap locks evolution (lock striping vs CAS), CopyOnWriteArrayList array copies, and BlockingQueue patterns.
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