odd-collections 1.0 — Unconventional Java data structures

odd-collections 1.0

Four original data structures that go beyond what the Java standard library offers — each with an unsynchronized and a thread-safe variant.

What's included

• ChunkyList — an unrolled linked list with pluggable growing/shrinking strategies, native Spliterator, and optimized bulk operations
• SymmetricMap — a bijective map with O(1) reverse lookup, strict/permissive insertion modes, and inverse map support
• TreeList — a sorted list with no duplicates, backed by an order-statistic red-black tree (O(log n) for all operations including indexed access), with live subList views
• MultiMap — a recursive multi-dimensional map with chained reads/writes and getOrCreate for on-the-fly level creation

Highlights

• Full java.util.List / java.util.Map compliance where applicable
• Thread-safe variants backed by ReentrantReadWriteLock with snapshot-based iterators
• All collections are Serializable
• JML contracts (@invariant, @requires, @ensures) on all classes
• 693 tests — 0 failures
• Clean Checkstyle and SpotBugs

Requirements

• Java 11 or later

License

https://www.gnu.org/licenses/lgpl-3.0.html