Errata 6

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(New page: The chapter 6 discusses '''protected abstract''' methods and says that removing such method is source compatible (page 89). In fact that was true until Java 5 appeared. However wit...)
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The [[chapter 6]] discusses '''protected abstract''' methods and says that removing such method is source compatible (page 89). In fact that was true until [[Java]] 5 appeared. However with the newly introduced ''@Override'' annotation this is no longer true.
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The [[chapter 6]] discusses '''protected abstract''' methods and says that removing such method is source compatible (page 89). In fact that was true until [[Java]] 5 appeared. However the newly introduced ''@Override'' [[annotation]] changed everything.
<source lang="java" snippet="anagram.ui.Anagrams"/>
<source lang="java" snippet="anagram.ui.Anagrams"/>

Revision as of 07:39, 8 October 2010

The chapter 6 discusses protected abstract methods and says that removing such method is source compatible (page 89). In fact that was true until Java 5 appeared. However the newly introduced @Override annotation changed everything. 

does not exists: anagram.ui.Anagrams

If you create a new version of public abstract class Anagrams dropping either getWordLibrary or getScrambler (or both), the @Override annotation in AnagramsWithConstructor will cause the compiler to complain: 

does not exists: anagram.ui.init

Source compatibility is gone. As an API designer of public class Anagrams you don't know whether your users (writing class AnagramsWithConstructor) will use @Override. As a result don't even try to remove protected abstract methods from an API. It was never good idea anyway and since Java 5 it is not backward compatible.

-- Rijk van Haaften, Oct 8, 2010

Retrieved from "http://wiki.apidesign.org/wiki/Errata_6"
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