Scala
Scala is the JVM-hosted functional/object-oriented language that powers Spark — the dominant distributed compute framework used by battery teams running large-scale analytics on cell-formation, end-of-line test, and fleet telemetry data. As a hard skill it requires fluency in Scala's type system (case classes, traits, implicits), the functional idioms (immutable data, higher-order functions), Spark's DataFrame and Dataset APIs, and the build and dependency tooling (sbt, Maven). Data engineers apply this when writing Spark jobs that join millions of cell-formation records with corresponding pack tests, when building streaming ingestion from Kafka into the data lake, and when refactoring Python prototypes into production-grade Spark for plant-wide deployment.
