Remove Setting Method

A field should be set at creation time and never altered.

Remove any setting method for that field.

image/svg+xml Employee setImmutableValue Employee

Corrections

Using Final

Paul Haahr kindly pointed out to me that I've not been accurate with the use of final in this refactoring. The point that I missed is that you can't use a final field if the initialization is done in a separate method to the constructor. This the example at the bottom of page 301 (that uses initialize(id)) just does not compile. (My apologies for not testing that fragment, some do slip through the net....) If you want to use a separate method, you can't make the field final

This also means that the mechanics is incorrect. Making the field final should be the last step not the first, and can only be done if it's possible.