'Handshake' not known in JAXB context

[Former user]

Hi,

I'm trying to create a Component however on first connect/login in throws an exception:

rocks.xmpp.core.XmppException: javax.xml.bind.JAXBException: class rocks.xmpp.extensions.component.accept.model.Handshake nor any of its super class is known to this context.
    at rocks.xmpp.core.session.XmppSession.throwAsXmppExceptionIfNotNull(XmppSession.java:232)
    at rocks.xmpp.extensions.component.accept.ExternalComponent.login(ExternalComponent.java:145)
    at rocks.xmpp.extensions.component.accept.ExternalComponent.connect(ExternalComponent.java:119)
    at rocks.xmpp.core.session.XmppSession.connect(XmppSession.java:248)
    at eu.siacs.formserver.Component.main(Component.java:13)
Caused by: javax.xml.bind.JAXBException: class rocks.xmpp.extensions.component.accept.model.Handshake nor any of its super class is known to this context.
    at com.sun.xml.internal.bind.v2.runtime.JAXBContextImpl.getBeanInfo(JAXBContextImpl.java:567)
    at com.sun.xml.internal.bind.v2.runtime.XMLSerializer.childAsRoot(XMLSerializer.java:467)
    at com.sun.xml.internal.bind.v2.runtime.MarshallerImpl.write(MarshallerImpl.java:308)
    at com.sun.xml.internal.bind.v2.runtime.MarshallerImpl.marshal(MarshallerImpl.java:163)
    at rocks.xmpp.core.session.XmppStreamWriter.lambda$send$18(XmppStreamWriter.java:112)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)

I'm able to work around that by adding Handshake manually to the JAXB Context like this:

XmppSessionConfiguration configuration = XmppSessionConfiguration.builder().extensions(Extension.of(Handshake.class)).build();

and passing this to the ExternalComponent constructor.

[Christian Schudt]

Do you have the source code imported directly into your IDE? I've seen similar issues as well, but only when not using the jar files.

It uses java.util.ServiceLoader to locate elements. If Handshake is not found, then likely all others won't be found as well. See class ExtensionModule.

Unfortunately I am not sure, how to tell the IDE to resolve these via ServiceLoader semantics. (it should look at META-INF/services/rocks.xmpp.core.session.Module).

[Daniel Gultsch]

Oh ok. I had a look into how Babbler is initially adding classes to the context and it does so by looking at the class path. - Which doesn't seem to work if you create fat jars...

[Christian Schudt]

I've only saw this issue once, on one machine using IntelliJ. Then later, it was gone again. I thought it was a bad setup or IntelliJ bug maybe.

[Daniel Gultsch]

Thanks for the explanation. I had to enable resource merging in my maven file.

https://maven.apache.org/plugins/maven-shade-plugin/examples/resource-transformers.html

[Christian Schudt]

Ah... not sure how you built it ;-) I went through this as well...

See xmpp-documentation/pom.xml, which builds an assembled jar file. (=> org.apache.maven.plugins.shade.resource.ServicesResourceTransformer)

maybe it helps.

[Daniel Gultsch]

Sorry in case this wasn't clear this issue can be closed. Just can't close it myself.