With each release of its solution, Alfresco provides a SDK bundle that allows to develop Alfresco Java extensions.
« Installation » of the SDK in Alfresco is pretty simple: use Eclipse import feature and select « SDK AlfrescoEmbedded » in the list of projects. That’s all!
I should have written « That was all » as, since release 4.0a, Eclipse indicates an error in the project :
The second error in list helps us finding the cause of the problem: « .classpath » XML file is not well formatted.
Looking at this file, we see that it starts with « space » characters:
Bad XML .classpath file
Just remove those characters in order file starts with <?xml… as every XML file should.
Now refresh your Eclipse project.
This time I really can write « That’s all! »
This bug is declared in Alfresco bug tracker: https://issues.alfresco.com/jira/browse/ALF-12166