Methods should always try to return a value that allows the developer to learn about the current state of the object and/or the result of an operation. This is consistent with the advice in EXP00-J. Do not ignore values returned by methods. The returned value should be as representative of the last known state as far as possible and should be designed chosen keeping in mind the perceptions and mental model of the developer.
...
To gain better ability at telling apart correct from fallacious results and enforcing that the incorrect results be carefully handled, a combination of the aforementioned approaches is recommended. At the same time, there are cases when an error value should be returned instead of an exception and vice versa. For instance, if some method is capable of failing in a variety of different ways, it is better to return failure codes than endeavoring to throw scores of different exceptions. Note that no possible failure codes should be within the range of the valid return values.
| Wiki Markup |
|---|
Sometimes a state testing method \[[Bloch 08|AA. Java References#Bloch 08]\] can be used to ensure that the object is in consistent state at all points in time. This approach is not useful in the absence of external synchronization. Also, there is a TOCTOU race condition between invocation of the object's state testing method and the call to a method that depends on the object's state. During this interval, the object's state could change surreptitiously. |
A method should not return a value or status error code that does not accurately specify the problemobject state. Clients should be able to rely on the value for performing critical decisions.
...
Compliant solution
This compliant solution recommends returning returns the result of the operation; true for success and false for failure.
...
This compliant solution returns the updated Node so that the developer can simply check for a null value lest the operation fails. Appropriate return Return values for methods can vary depending on the control flow or the information that the developer finds more useful.
...
Failure to provide appropriate feedback through status codes or return values, error codes and exceptions can lead to inconsistent object state and unexpected program behavior.
...