Home/ Questions/Q 406767
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-12T17:31:43+00:00

In class today, my professor was discussing how to structure a class. The course

  • 0

In class today, my professor was discussing how to structure a class. The course primarily uses Java and I have more Java experience than the teacher (he comes from a C++ background), so I mentioned that in Java one should favor immutability. My professor asked me to justify my answer, and I gave the reasons that I’ve heard from the Java community:

  1. Safety (especially with threading)
  2. Reduced object count
  3. Allows certain optimizations (especially for garbage collector)

The professor challenged my statement by saying that he’d like to see some statistical measurement of these benefits. I cited a wealth of anecdotal evidence, but even as I did so, I realized he was right: as far as I know, there hasn’t been an empirical study of whether immutability actually provides the benefits it promises in real-world code. I know it does from experience, but others’ experiences may differ.

So, my question is, have there been any statistical studies done on the effects of immutability in real-world code?

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    I would point to Item 15 in Effective Java. The value of immutability is in the design (and it isn’t always appropriate – it is just a good first approximation) and design preferences are rarely argued from a statistical point of view, but we have seen mutable objects (Calendar, Date) that have gone really bad, and serious replacements (JodaTime, JSR-310) have opted for immutability.

    • 0