Dynamic References

Dynamic References

Bnd discovers package dependencies in a bundle by scanning the bytecode of the compiled Java files. This process finds all of the static dependencies of the Java code, but it does not discover dynamic dependencies, for example those arising from the use of Class.forName(). There is no generic way for Bnd to calculate all dynamic dependencies. However there are certain well-known configuration formats that result in dynamic dependencies, and Bnd can analyse these formats through the use of plugins.

For example, some bundles use the Spring Framework for dependency injection. Spring uses XML files that refer to fully qualified Java class names:

<bean id="myBean" class="org.example.beans.MyBean">
</bean>

Here the org.example.beans package is a dependency of the bundle that should be added to Import-Package. Bnd can discover this dependency by adding a Spring analyser plugin via a declaration in the descriptor file:

-plugin: aQute.lib.spring.SpringComponent

Similar plugins exist for JPA and Hibernate, and custom plugins can be written to support other configuration formats or scripting languages.