Calling a method and passing a reference to an object and catching a return using the same link

Question

I have a beginner question. I searched a lot for an answer, but could not find the exact answer, so maybe some of the more experienced developers can help me with this.

So, let's say you have the following situation in your code (this is a simplified version of the situation):

SomeObject a1 = new SomeObject(); a1 = someMethod(a1); public SomeObject someMethod(SomeObject a1) { a1.changeVariable(); return a1; } 

I have now heard from several people saying that passing an object reference to a method and catching the return value is the wrong coding practice. Unfortunately, no one can explain to me exactly why this is a bad coding practice, and my search for the reason came up with nothing. Can anyone explain why this is bad practice? I can’t come up with a situation where something for this could go wrong.

Thank you in advance, you good people have already helped me with answers to other people countless times, this is the first time I really needed to ask a question :)

Answer 1

There is no obvious benefit to the scenario you showed. However, as a sample, this may be useful in my experience - especially if the method performs validation.

Guava Preconditions.checkNotNull is a great example of this. This means that I can write code like this:

 public class Player { private final String name; public Player(String name) { this.name = Preconditions.checkNotNull(name); } } 

... instead of separating assignment and verification. It also allows validation to exist as part of another call, for example. to another constructor:

 super(Preconditions.checkNotNull(name));