Pico Containers (Java)

Tiny dependency injection framework. Supposedly was used as the base for the JetBrains IDEA IDEs.

Components are registered to a container. This includes the "interfaces" a component requires to be instantiated or provides to the container.

Components are instanced by asking the container for a specific component.

Behaviors: a container can have "behaviors" added that alter how it responds to requests.

Caching: a.k.a. "singleton mode." Ensures a component is instanced once and the same instance is returned on future creation attempts.

Ambiguous component exception: when the container does not know which dependencies to use to satisfy a request.

Using context to select which components to inject; such as explicit context tags or using reflection magic. Sometimes parameter names are even used.

Required instances are provided to a component's constructor, or by calling a setter, or by directly assigning values to fields.