difference between null != something and something != null

Question

Is there a difference between null != something and something != null in Java. And if there is a difference then which one should I use and why??

Answer 1

I just want to point out that the "Yoda condition" rationale for doing this (in languages like C & C++) does not apply in this (Java) case.

1. Java does not allow general expressions to be used as statements, so both

    something == null;
   

   and

    null == something;
   

   would be compilation errors.

2. The types of something == null and something = null are different; boolean and some reference type respectively. In this case, it means that both:

    if (something = null) {
        ...
    }
   

   and

    if (null = something) {
        ...
    }
   

   would be compilation errors.

In fact, I can't think of a realistic example where null == something would be compilation error and something == null would not. Hence, it doesn't achieve anything in terms of mistake-proofing.