Lifecycle of a bean

During this step, kernel creates instance of the class which was registered for this bean (for more details see Registration of a bean). Instance of a bean is created using paremeterless constructor of a class.

In this step kernel passes class instance of a bean to the configurator bean (an instance of BeanConfigurator if available), for configuring it. During this step, BeanConfigurator instance, which is aware of the configuration loaded from the file, injects this configuration to the bean fields annotated with @ConfigField annotation. By default configurator uses reflections to access those fields. However, if a bean has a corresponding public setter/getter methods for a field annotated with @ConfigField (method parameter/return type matches field type), then configurator will use them instead of accessing a field via reflection.

At the end of the configuration step, if bean implements ConfigurationChangedAware interface, then method beanConfigurationChanged(Collection<String> changedFields) is being called, to notify bean about field names which values has changed. This is useful, if you need to update bean configuration, when you have all configuration available inside bean.

At this point kernel looks for the bean class fields annotated with @Inject and looks for a value for each of this fields. During this step, kernel checks list of available beans in this kernel, which matches field type and additional constraints specified in the annotation.

When a required value (instance of a bean) is found, then kernel tries to inject it using reflection. However, if there is a matching getter/setter defined for that field it will be called instead of reflection.

When bean is configured and dependencies are set, then initialization of a bean is almost finished. At this point, if bean implements Initializable interface, kernel calls initialize() method to allow bean initialize properly if needed.