Assert.notNull(newModuleDefinitionSource, "moduleDefinitionSource is required as it specifies the new module definition to apply in " + this.getClass().getName());
RootModuleDefinition newModuleDefinition = newModuleDefinitionSource.getModuleDefinition();
RootModuleDefinition oldModuleDefinition = getExistingModuleDefinitionSource(application);
ModificationExtractorType modificationExtractorType = getModificationExtractorType();
// figure out the modules to reload
ModificationExtractor calculator = getModificationExtractorRegistry().getModificationExtractor(modificationExtractorType);
TransitionSet transitions = calculator.getTransitions(application, oldModuleDefinition, newModuleDefinition);