Unexcepted return value when using ifPresentOrElse lamba function

Question

I can't seem to figure out why I'm getting this error on the IDE Unexpected return value when I need to return something from a method when using lambda.

public Employee getEmployee(long id) {
repository.findById(id).ifPresentOrElse(
                empDetails -> {
                    return service.buildEmployee(empDetails);
                },
        () -> { throw new ResourceNotFoundException(); }
        );

}

Thank you!

@Stultuske the 'Unexpected return value'. I'm not sure what's the cause.. — mengmeng, Mar 16 '20 at 11:03
Would you realize what problem with this code without any error messages or stack trace? — slesh, Mar 16 '20 at 11:03
@M.Ismail hi thanks! I've updated my question to be more clear. It's an error on the IDE. — mengmeng, Mar 16 '20 at 11:05

score 2 · Accepted Answer · answered Mar 16 '20 at 11:05

2

ifPresentOrElse is used to consume the Optional's value if present, and to perform some other logic otherwise. It cannot be used to return a value or throw an exception.

Instead you can combine map with orElseThrow:

public Employee getEmployee(long id) {
    return repository.findById(id)
                     .map(service::buildEmployee)
                     .orElseThrow(ResourceNotFoundException::new);
}

answered Mar 16 '20 at 11:05

Eran

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Thanks for this! I'll accept your answer in 3mins. :) – mengmeng Mar 16 '20 at 11:12

Unexcepted return value when using ifPresentOrElse lamba function

1 Answers1