When should I use Import-Package and when should I use Require-Bundle?

Question

OSGi allows for dependencies to be determined via Import-Package, which just wires up a single package (exported from any bundle), and Require-Bundle

Answer 1

Avoid Import-Package. As packages provide many-to-many relationships between bundles, they are prone to dependency cycles that are hard to detect and avoid.

Require-Bundle on the other hand, references a single bundle, making dependency graph protected from cycles by a trivial build-time check. With Require-Bundle it is much easier to build layered architecture with isolated lower level of abstraction.