Given the type hierarchy defined below, Choose the most correct statement below?

trait A{ def a = 1 } trait X extends A{ override def a = { println("X") super.a } } trait Y extends A{ override def a = { println("Y") super.a } } For the expression val xy = new AnyRef with X with Y

For the type heirachy defined below, Choose the most correct statement below for the output?

Which one is false about Futures and Promises?

Best description for the variance expression as following?

In Scala everything is an Object, No ___?

Option that best describes the difference between a var and val definition in Scala?

Choose correct output using the code?

How to groupBy using multiple columns in Scala collections?

Output of following code?

For the code below, Choose the correct statement that describes an issue with the code?

Choose output of given code below?