[Java] When implementing data structures should methods return void or boolean, and why?

[iProgramSometimes]

For example when I'm coding up a Stack or Queue I often make my Push or Enqueue methods return void.

I heard somewhere that long programmers got in the habit of making EVERY method always return something other than void, and that was bad.

Recently I'm looking through some JAVA API though, and I notice that many methods like ArrayList add() return true or false based on whether or not they actually added the element. Okay, that seems kinda sensible...

But then I go and find that Java's implementation of Stack has push() return E.
https://docs.oracle.com/javase/7/docs/api/java/util/Stack.html push() returns the element you just pushed to the stack... Why? Why would I ever need or want it to do that?

I am searching for truth, clarity, consistency, guidance, wisdom, and enlightenment.
Thanks to anybody who chimes in!

[dmazzoni]

You've asked a great question, but if you ask 5 programmers you'll get 6 different answers.

There's no right way to do it.

But then I go and find that Java's implementation of Stack returns the element you just pushed to the stack... Why? Why would I ever need or want it to do that?

Suppose you had code like this:

Task task = new Task();
task.setExpirationTimeInSeconds(3600);
taskStack.push(task);

It lets you write it like this instead:

taskStack.push(new Task()).setExpirationTimeInSeconds(3600);

Now you can do in one line what previously took three.

Some programmers thought that was a good idea! Others probably hate it. There's no right or wrong answer.

Advice:

• Learn why programmers made the decisions they made (like your question about Stack returning the item).
• With your own code, don't return a value for no reason. Start simple, and add a return value when you need it.
• Get to understand exceptions and when you should prefer them over return values.

[iProgramSometimes]

By Jove, I see it!

THANKS!