GuideTechnology
13 min read
What the angle brackets mean and why they exist. Generic classes and methods, bounded types, why List of Integer is not a List of Number, wildcards with extends and super, the PECS rule that makes them make sense, and type erasure with its practical consequences.
GuideTechnology
12 min read
How to sort objects with Comparable and Comparator, how queues, deques and priority queues work, why ArrayDeque replaces the legacy Stack, and a decision guide with complexity and memory trade-offs for choosing the right collection.
GuideTechnology
14 min read
How Java stores key-value pairs, and how HashMap finds a value in constant time: hashing, buckets, collisions, resizing and treeification, explained with a small map you build yourself. Plus LinkedHashMap, TreeMap, the everyday Map methods, and the mistakes that corrupt a map.
GuideTechnology
12 min read
How Java's collections framework is organised, how ArrayList and LinkedList really differ, what makes a Set unique, how to remove items safely while iterating, and the confusing differences between List.of, Arrays.asList and unmodifiable views. Includes sequenced collections from Java 21.
