+ * Utility for obtaining an implementation of the {@link InjectorFactory} using
+ * {@link ServiceLoader} and for obtaining a {@link SimpleInjector}.
+ *
+ * The builder takes care that the factory and simple injector are built only once.
+ * For test code, make sure to call {@link #setInjectorFactory(InjectorFactory)}
+ * before each test case to force the retrieval of a new factory and injector. This
+ * is important because if the simple injector is not created again it will use
+ * cached {@link Injector} instances from other tests.