How does Scala achieve immutability at scale in large distributed systems?

Scala uses immutable data structures and structural sharing to make large-scale systems safer and more predictable.

In distributed systems, immutability ensures that once data is created, it cannot be modified. Scala’s immutable collections (like List, Vector, Map) use structural sharing, meaning updates create new versions without copying everything. This reduces memory overhead while improving concurrency safety. In systems like Spark, immutability allows deterministic execution across distributed nodes, avoiding race conditions and inconsistent states.