Scala

Preferring immutable values (val) over mutables is the basis of Scala's safe style.

In Scala nearly everything is an expression that returns a value, which reshapes your thinking.

Scala offers a cleaner object model than Java with case classes and objects.

Scala's collections library is among its strongest features; mastering it multiplies your output.

Pattern matching is one of Scala's most elegant tools, solving problems with clear, concise code.

Pure functions and the absence of side effects make code predictable and testable.

In Scala we model absence and errors as types, instead of exceptions or null.

Scala's type system is among the most powerful, and variance is key to understanding libraries.

The givens/implicits mechanism is the secret of Scala's flexibility and the basis of type classes.

Type classes give you powerful polymorphism without inheritance.

Scala offers safe, elegant concurrency models compared to raw threads.

Mastering sbt and testing makes large projects maintainable and trustworthy.

Scala is the language of Apache Spark — a huge door into data engineering.