Author Archives: Stanislav_Panteleev

Yes, a HashMap can degenerate into a linked list even if the keys have different hashCode() values, under certain conditions. Let me explain how and why. 🔍 How HashMap organizes entries: Each key’s hashCode() is used to determine its bucket … Continue reading →

✅ Estimated Time Complexity of HashMap operations Operation Average Case Worst Case (pre-Java 8) Worst Case (Java 8+) get(key) O(1) O(n) O(log n) (with tree bins) put(key, value) O(1) O(n) O(log n) remove(key) O(1) O(n) O(log n) containsKey() O(1) O(n) … Continue reading →

In Java, the initial number of buckets in a HashMap depends on the constructor used when creating the map. By default: 👉 The initial capacity is 16 buckets. Key details: Initial Capacity: 16 (this means 16 buckets internally). Load Factor: … Continue reading →

🎯 TL;DR: ✅ HashMap can store multiple keys with the same hashCode() as long as equals() returns false — because it uses both hashCode() and equals() to handle collisions properly.

🧠 Hash Table Implementations (per Knuth & CLRS) 1. Chaining Each bucket contains a list (or tree) of entries. Collisions are handled by appending to that list. 2. Open Addressing All entries live in the array itself. On collision, we … Continue reading →

🔧 How is a HashMap constructed? 🔹 At a high level, a HashMap is: A hash table implementation that maps keys to values using a combination of array + linked list + (sometimes) red-black trees.

✅ Yes — SortedMap is an interface in Java. It is part of the Java Collections Framework, and it defines the contract for a map that maintains sorted order of keys.

🔍 What is LinkedHashMap? LinkedHashMap is a hash table + doubly linked list implementation of the Map interface.It maintains the insertion order (or access order) of entries, unlike regular HashMap.

🧩 What is a WeakHashMap? A WeakHashMap is a hash table-based map where the keys are stored as weak references. If a key is no longer referenced elsewhere in your application, then the entry will be automatically removed by the … Continue reading →

🔍 Quick Refresher Reference Type get() returns? Enqueued when? Common Use Case WeakReference ✅ the object When object is weakly reachable WeakHashMap, caches PhantomReference ❌ always null After finalization, before GC reclaims Cleanup, monitoring, resource release