Erlang Coding Standards – Return Value Conventions

I use both, depending on the method. For example, in a method that decides something, i think that

public boolean isSunday(Calendar cal) {
  if (Calendar.SUNDAY == cal.get(Calendar.DAY_OF_WEEK))
    return true;
  else
    return false;
}

captures the intent of the method better. It is stateless, it is not supposed to be extended, and it is closed in that the if-clause generates all values the method may ever return.

If the method calculates something, or retrieves information, i like the second variant more:

public String getAnswer(int question) {
  if (isAvailable(preciseAnswerService)
    return preciseAnswerService.answer(question);
  return defaultAnswer(question);
}

Here, the fact that one answer is chosen over the other depends on the state of the answerService. We might extend the method later by adding a preciseAnswerCache, or retrieve the answer from somewhere else.

How is this normally done in Java?

Painfully.

One option is to use an array, like this Python snippet that returns a list or tuple...

Another option would be to return a hash/dict, like this JavaScript example...

These techniques don't work well in Java; the values would have to be downcast from Object.

One more would be to create a custom object just for this purpose, like this Java example...

This is most common, but it is tedious to create all those little classes. In C++ it is common to use std::pair but this is not commonly done in Java.

With Lombok it is quite easy to create little custom objects:

@RequiredArgsConstructor
public class X {
  private final boolean status;
  private final byte[] data;

}