Butterfly Container is a Java dependency injection container. It is smaller (~100KB jar), yet more flexible and easier to use than Spring, Pico, and Guice (at least in the developers' opinion). Instead of XML, Butterfly Container is configured using a simple, flexible, Java-like configuration language, or by plugging plain non-annotation, non-reflection Java factories into the container. There are no external dependencies. License: The Apache License 2.0 Changes:
This release makes it possible to replace factories in the container at runtime. Factories that reference the replaced factory will automatically be updated to reference the new factory. The factory replacement feature is handy when unit testing a component using mock objects. Replace a real factory with a mock object factory to test if the component uses this collaborator (the mock object) correctly.

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