Is Ruby Replacing Java? – Not So Fast

Okay, I have heard it all: Ruby On Rails (RoR) is so much cooler and simpler than Java EE. It allows you to write web applications 10X faster. And Ruby has nifty language features we can only dream of in Java. So, Ruby must be replacing Java to become the "next" programming language just as Java "replaced" C++/COBOL and C++ "replaced" Fortran.

Well, in my opinion, this kind of talk has some serious logical problems. First of all, as the short history of high technology has proven again and again, the "superior" solution does not always win over "inferior" ones. In fact, the opposite is more likely to be true. The question regarding to Ruby versus Java is NOT how much more advanced RoR is compared with Java EE -- the real question is whether Java EE is good enough for most developers.

The reason, in economics terms, is that the choice of a technically "better" programming language does not bring you competitive advantage in terms of overall cost and productivity. Instead, it matters far more to have better requirement gathering, better customer feedback, better development process, better trained developers, and better development tools (e.g., IDEs). In software engineering speak, the actual implementation of a system using a specific programming language has the lowest value in the value chain, and can be easily outsourced.

Okay, now you may ask: "If that is true and programming language does not matter, how come Java became so successful and replaced an array of older languages?" Well, did Java really "replace" any other language? I have recently been in graduate school for a science PhD program, and all the new bleeding-edge number crunching software we wrote was still Fortran. It is not being replaced by C++ or Java. Fortran is good enough and switching to a cooler language does not make scientific computing better / faster -- and the re-training cost for the entire team eliminates any potential productivity gain. Another example: for rich UI application developers, the dominant languages are still C / C++ / VB. Even heavily marketed languages like C# and VB.Net have little traction -- let alone Java.