Struggle against habits formed by Java when migrating to Scala

Question

What are the most common mistakes that Java developers make when migrating to Scala?

By mistakes I mean writing a code that does not conform to Scala spirit, for example

Answer 1

Using Arrays.

This is basic stuff and easily spotted and fixed, but will slow you down initially when it bites your ass.

Scala has an Array object, while in Java this is a built in artifact. This means that initialising and accessing elements of the array in Scala are actually method calls:

//Java
//Initialise
String [] javaArr = {"a", "b"};
//Access
String blah1 = javaArr[1];  //blah1 contains "b"

//Scala
//Initialise
val scalaArr = Array("c", "d")  //Note this is a method call against the Array Singleton
//Access
val blah2 = scalaArr(1)  //blah2 contains "d"