Should a retrieval method return 'null' or throw an exception when it can't produce the return value?

I am using java language,I have a method that is supposed to return an object if it is found.

If it is not found, should I:

• return null

• throw an exception

• other

Which is the best practise or idiom?

If you are always expecting to find a value then throw the exception if it is missing. The exception would mean that there was a problem.

If the value can be missing or present and both are valid for the application logic then return a null.

More important: What do you do other places in the code? Consistency is important.

Stack Overflow Q#175532, score: 534