Cannot start Jetty 11 websocket server on OSGi

[freyssin]

Jetty version(s)
Jetty 11.0.18

Java version/vendor (use: java -version)
JDK 11.0.20.1

OS type/version
Windows 10

Description
We are trying to migrate our websocket services from Jetty 9.4.x to 11.0.x, we encounter 2 OSGi issues.

We have been using OSGi and Felix in the OW2/Joram project for many years. We have a working setup with Felix (7.0.5), Jetty 9.4, Felix Http and Jetty websocket bundles. Recently we upgraded our libraries to JEE 10: Jetty 11.0.18, Jersey 3.1.3, Felix Http (5.1.6). Our Rest services work correctly on this new platform, unfortunately we cannot find a working configuration for our websockets server.

We found a minimum configuration with the following bundles:

file:./bundle/slf4j-api.jar
file:./bundle/slf4j-jdk14.jar
file:./bundle/jetty-xml.jar
file:./bundle/jetty-webapp.jar
file:./bundle/websocket-jetty-api.jar
file:./bundle/websocket-jetty-common.jar
file:./bundle/websocket-core-common.jar
file:./bundle/websocket-servlet-11.0.18.jar
file:./bundle/websocket-core-server-11.0.18.jar
file:./bundle/websocket-jetty-server.jar
file:./bundle/org.apache.felix.http.servlet-api.jar
file:./bundle/org.apache.felix.log.jar
file:./bundle/org.apache.felix.http.jetty.jar

But during startup we have the following errors:

ERROR: Bundle org.eclipse.jetty.webapp [4] Error starting file:./bundle/jetty-webapp.jar (org.osgi.framework.BundleException: Unable to resolve org.eclipse.jetty.webapp [4](R 4.0): missing requirement [org.eclipse.jetty.webapp [4](R 4.0)] osgi.extender; (osgi.extender=osgi.serviceloader.processor) Unresolved requirements: [[org.eclipse.jetty.webapp [4](R 4.0)] osgi.extender; (osgi.extender=osgi.serviceloader.processor)])

ERROR: Bundle org.eclipse.jetty.websocket.common [6] Error starting file:./bundle/websocket-jetty-common.jar (org.osgi.framework.BundleException: Unable to resolve org.eclipse.jetty.websocket.common [6](R 6.0): missing requirement [org.eclipse.jetty.websocket.common [6](R 6.0)] osgi.extender; (osgi.extender=osgi.serviceloader.registrar) Unresolved requirements: [[org.eclipse.jetty.websocket.common [6](R 6.0)] osgi.extender; (osgi.extender=osgi.serviceloader.registrar)])

The 2 errors above seem to be due to OSGi extensions requested by the "org.eclipse.jetty.webapp" and "org.eclipse.jetty.websocket.common" bundles. I searched in the Jetty code and these annotations appeared from version 10:

• For the websocket-jetty-common bundle, the origin seems to be the correction of issue Review jetty jars that contain META-INF/services/org.eclipse.jetty.webapp.Configurations for correct osgi manifest headers #6423 (PR Jetty 10.0.x 6423 service provider osgi headers #6424).
• For the jetty-webapp bundle, the origin seems older but linked to the branches of versions 10 and 11.

Is this behavior correct? If so, what should I do to get around it? What would then be the correct OSGi configuration to start a Jetty websocket server with OSGi and more especially Felix?

PS: This problem may also be related to #6418.

[freyssin]

There is a similar issue with the websocket client bundle:

ERROR: Bundle org.eclipse.jetty.websocket.client [28] Error starting file:./bundle/websocket-jetty-client.jar (org.osgi.framework.BundleException: Unable to resolve org.eclipse.jetty.websocket.client [28](R 28.0): missing requirement [org.eclipse.jetty.websocket.client [28](R 28.0)] osgi.extender; (osgi.extender=osgi.serviceloader.registrar) Unresolved requirements: [[org.eclipse.jetty.websocket.client [28](R 28.0)] osgi.extender; (osgi.extender=osgi.serviceloader.registrar)])

[freyssin]

After adding an implementation of osgi.serviceloader.registrar/osgi.serviceloader.extender (spifly) all bundles are now correctly loaded.

However, I did an experiment by manually editing the manifests of the erroring bundles (*1) to remove the Require-Capability line and it seems to work. Would it be possible to generate these bundles without this mandatory dependency on spifly (or equivalent)?

(*1) jetty-webapp.jar, websocket-jetty-common.jar and websocket-jetty-client.jar.

[joakime]

The Require-Capability is a requirement to allow java.util.ServiceLoader to work.
Removing support for java.util.ServiceLoader is not a valid setup for Jetty.

Jetty 9 had few usages of java.util.ServiceLoader, but the upgrade to Jakarta EE 9 / Jetty 11, means that java.util.ServiceLoader is now a mandatory requirement for things to function properly across many things within Jetty itself, and it's various dependencies.