OSGi manifest needs work for ServiceLoader behavior

[joakime]

ServiceLoader use is not a feature supported by OSGi.

On Eclipse Equinox, ServiceLoader support does not exist in any form. On Apache Felix, ServiceLoader support exists, but as an optional extension.

The recommendations by Eclipse for projects that are both OSGi and using ServiceLoader is to declare that the jar uses a ServiceLoader and to set that support to optional.

The nuances of this are beyond my understanding, so I'll have to defer to experts on this.

Some documentation on all of this ...

• https://www.eclipse.org/forums/index.php/t/474446/
• https://en.wikipedia.org/wiki/OSGi_Specification_Implementations#133:_Service_Loader_Mediator_Specification
• https://blog.osgi.org/2013/02/javautilserviceloader-in-osgi.html