The Injector Creation Process

Overview of the Injector creation process

Guice builds an injector using configuration modules. If there are errors at the end of any phase, injector creation is halted and a CreationException is thrown.

Phase 1: Static Building

In this phase, Guice interprets elements, creates bindings, and validates the configuration. The only user code executed in this phase is Module.configure().

This is the only phase executed for Stage.TOOL.

Phase 2: Injection

During this phase, objects will be injected on-demand if necessary. For example, if satisfying a static injection requires a provider instance, the provider will be injected before it is used. If initialized objects are circularly dependent, the order of injection is undefined.

First, statics registered via requestStaticInjection() are injected. Next, instances that are the arguments to requestInjection(), toInstance() and toProvider() are injected.

Phase 3: Singleton Preloading

In Stage.PRODUCTION, all singletons are created. In Stage.DEVELOPMENT, only bindings scoped using asEagerSingleton() are created.