Explore hash tables, hash maps, and hash sets with animated hashing, collisions, buckets, operations, and responsive controls.
Hash a key, watch it travel to a bucket, and see how chaining and rehashing preserve fast lookups.
Bucket stage
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The hash function and buckets work the same way in all modes. A Hash Table stores keys, a Hash Map connects each key to a value, and a Hash Set rejects duplicate keys. Collisions are resolved here with separate chaining.
Average lookup
O(1)
Collision handling
chain
Resize threshold
0.75
Concept guide
Review the mental model, tradeoffs, and practical use cases after you experiment.
Three fundamental hash-based structures with distinct characteristics.Hash Table provides thread-safe key-value storage, Hash Map offers high-performance unordered mappings, and Hash Set ensures unique element storage using hash codes.
Linked lists or probing
Built-in locking
No null keys/values
No insertion order
Since Java 1.0
Synchronization overhead
Java 8+ implementation
Requires external sync
1 null key, multiple null values
LinkedHashMap maintains order
Java 1.2+
No synchronization
Uses map internally
Unique elements only
Single null element
LinkedHashSet for order
Use Collections.synchronizedSet
Constant time operations
| Operation | Hash Table | Hash Map | Hash Set |
|---|---|---|---|
| Add/Insert | put(key, value) | put(key, value) | add(element) |
| Lookup | get(key) | get(key) | contains(element) |
| Remove | remove(key) | remove(key) | remove(element) |
| Iteration | Enumeration | Iterator | Iterator |
| Size | size() | size() | size() |
