Scala

Scala combines object-oriented and functional programming in one concise, high-level language. Scala is a strong statically typed general-purpose programming language which supports both object-oriented programming and functional programming. 

This key competency includes a deep understanding of OOPS concepts in Scala, Traits, Access Modifiers, Arrays, Strings, among others. 

Key Competencies: 

1. Scala OOPS - A deeper understanding of OOPS concepts and their use in Scala - namely, objects and classes, constructors, method overloading, method overriding, inheritance, among others. 
2. Scala Trait - Understanding of trait in Scala, a collection of abstract and non-abstract methods. Ability to implement members of a trait in comparison to interfaces in Java. 
3. Access Modifiers - Understanding the private, protected and public modes and using access modifiers to provide/revoke accessibility to classes, traits, data members, member methods and constructors etc. 
4. Arrays, Strings, and Sequences - Ability to work with generic arrays, string manipulations, and sequence operations. 
5. Scala Exception Handling - Understanding of unchecked exception handling in Scala - including try catch, finally, throw, throws, and writing custom exceptions.