What was it like when you switched from Java to Scala?

I get asked this question a lot. My answer is always similar. This post represents the long form of that answer.

I started programming in 2005, during my freshman year at Rutgers University. My first course was in C. C is well suited to procedural programming and, I seemed to take to this style very well.

After C was C++. Object Orientation did not click for me. I didn't understand why someone would:

  1. Build a data structure
  2. Seal all the data from access
  3. Add semantics to the data structure itself for mutation

It seemed quite unintuitive to me. Why not just create a struct and write functions to process instantiations? Why couple data to usage? C++ seemed to me like an unnecessary complication over an otherwise simple idea.

When I was instructed in Java things were even more confusing. Like C++, Java preferred Object Orientation. Even more problematic, Java enforced OO practices. Now, in order to do anything, I needed to first build a class. Need to add two integers? Build a class. Need to print "Hello World!" to console? Build a class. Need to find the 17th  prime? Build a class.

Given my attraction to procedural programming and aversion from OO, its not surprising a lot of my Java looked like:

class Clazz{public int a; public String b;}
class Processing{
  public static Clazz doSomething(Clazz c){...}
  public static String asCsv(Clazz c){...}

After some time, I found the demands of my profession starting to become too large for the time I could put into it. I had to find another way of doing things. I hit the books and papers. I read about many programming languages and many paradigms. I had two immovable restrictions:

  1. I was bound to the JVM
  2. I needed to interoperate with legacy Java and C++ code

I had decided I would choose between Ceylon and Scala. For me Scala was a better choice.

Functional Programming meshed nicely with my procedural programming style. The scalaz and typelevel communities focused on functional, pure constructs and turned away from effectful OO design. Furthermore, Scala's interoperability with Java was far superior to Ceylon's at the time making it easy for me to build interfaces that could integrate seamlessly with legacy POJO and JNI code.

For me, switching from Java to Scala was easy and straight forward. I already had a propensity toward the functional paradigm and I never got into the OO craze to begin with.