9 docs tagged with "collections"

Consolidated interview Q&A for the Java Collections Framework — hierarchy, List, Set, Map, Queue, iterators, sorting, and immutability — from beginner through advanced.

The complete interface tree of the Java Collections Framework — Iterable, Collection, List, Set, Queue, and why Map stands apart.

How to create truly immutable List, Set, and Map instances in Java using the Java 9+ factory methods and how they differ from the older Collections.unmodifiable wrappers.

How the Iterator protocol works, what ConcurrentModificationException means and how to avoid it, and how the enhanced for-each loop is compiled.

Understand Java's List interface, when to use ArrayList vs LinkedList, and how their internal structures drive performance trade-offs.

Deep dive into Java's Map implementations — how HashMap buckets work, when to use LinkedHashMap or TreeMap, and why ConcurrentHashMap is the thread-safe choice.

Understand Java's Queue and Deque interfaces, how ArrayDeque and PriorityQueue work internally, and when to use BlockingQueue for producer-consumer patterns.

Understand Java's Set interface, how each implementation handles uniqueness and ordering, and when to choose HashSet, LinkedHashSet, or TreeSet.

Understand the difference between Comparable (natural ordering defined on the class) and Comparator (external ordering strategy), and how to use both with collections, streams, and sorted data structures.