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1. Package dependencies. A bundle can export a package which others import. These dependencies, although dynamic, are relatively easy to handle and the whole resolution process is handled by the OSGi framework for you.
2. Service dependencies. Services, implemented by components inside of bundles, can have their own life cycle within that of their containing bundle and therefore can be registered and unregistered at any time. Other components often depend on these services and need to deal with changes in their availability.

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• Provide a clean separation between a service component implementation and the "glue" that binds it to the OSGi framework. The service component implementation should not have to contain any OSGi specific code. In other words, it should be a POJO (Plain Old Java Object).
• Minimize the amount of code that needs to be written. The specification and management of dependencies should be automated as much as possible, whilst still providing enough flexibility to customize the system.
• Be extensible. Even though the core bundle provides a lot of different dependencies already, you should be able to add your own types of dependencies easily.
• Easy to monitor and debug. Being a dynamic system, it's important to be able to see what the state of all components and dependencies are at any point in time.
• Supporting powerful high level design patterns. When building real-world applications, more complex patterns need to be used, such as aspects and adapters. Support for these needs to be built into the core.