Most java developers have a really solid grasp of object-oriented concepts and patterns, which makes the transition to ruby easy really easy from that perspective. Moving from a statically typed to dynamic language is still a big change and some of the more basic coding practices change significantly. Here are some recommendations I’ve come up with based on my experiences doing mentoring with a bunch of java developers transitioning to ruby on our team and some code patterns I’ve heard used by a colleague of mine who is also mentoring some java developers who are transitioning to ruby.

Hints

• Minimize the use of class variables – ruby’s class variables have some strange inheritence rules, and, with multi-process web containers, they don’t act as singletons across all instances of an app on the same server anyway.
• Prefer local variables over instance variables when possible. Minimizing the scope of a variable in a dynamic language reduces the possibility of bugs and makes it much easier to see where the variable is being set and used.
• Don’t pre-initialize data structures – no need. Arrays and hashes are dynamic and in the vast majority of circumstances pre-sizing them does not help performance and just leads to more noise in your code.
• Snake-case variables .. thing_one and thing_two.
• Semi-colons are not needed at the ends of statements ; only use them when doing single-line method definitions or rare cases where you want two statements on the same line.
• Prefer composition over complex inheritence trees.
• Prefer mixins over complex inheritence trees.

Tips

• Explore code with irb or Pry. No faster way to get conversant with ruby than to explore using it from a ruby-based shell!