If you start at the bottom of that page, you will see that I moved the XMLPersistenceExtensionFactory.getItemBuilders() operation to ItemBuilder. If you look at ItemBuilder.getItemBuilders() you will see that the only difference from the original is that I added a line to create a logger. For every interface where you do this, you need to also create a test for it. See ItemBuilderTester, which I also just committed, for an example. (Your tests should look nearly identical.)
Aside from that, the only things to watch out for are Java Versions and whether or not you should return an array or a single instance. In the first case, if your code will not compile and says the new static interface method isn't found, then you need to update the Execution Environment in your Manifest file and the Java Build Path (right click and select Properties) to both say Java 1.8. In the latter, that depends on whether you are pulling a single service or multiple instances of the same service.
You can get started on this in Core.java. Lines 263 to 279 can be replaced with four lines:
