ClassNotFoundException for registered response writer

[kevinstier]

I have the following response writer:

@Produces("application/json")
public class DefaultResponseWriter<T> implements HttpResponseWriter<T> {

    @Override
    public void write(T result, HttpServerRequest request, HttpServerResponse response) {

        if (result != null) {
            response.end(JsonUtils.toJson(result, DatabindCodec.mapper()));
        }
        else {
            response.end();
        }
    }
}

Which is basically the same as the provided JsonResponseWriter, except for the @Produces("application/json"). When I register this writer as

RestRouter.getWriters().register(DefaultResponseWriter.class);

I receive the following exception:

java.lang.RuntimeException: java.lang.ClassNotFoundException: org.glassfish.jersey.internal.RuntimeDelegateImpl
	at javax.ws.rs.ext.RuntimeDelegate.findDelegate(RuntimeDelegate.java:130)
	at javax.ws.rs.ext.RuntimeDelegate.getInstance(RuntimeDelegate.java:97)
	at javax.ws.rs.core.MediaType.toString(MediaType.java:395)
	at java.lang.String.valueOf(String.java:2994)
	at java.lang.StringBuilder.append(StringBuilder.java:131)
	at com.zandero.rest.writer.WriterFactory.register(WriterFactory.java:158)
	at com.zandero.rest.writer.WriterFactory.register(WriterFactory.java:96)
	at demo.rest.Api.start(Api.java:173)
	at io.vertx.core.AbstractVerticle.start(AbstractVerticle.java:106)
	at io.vertx.rxjava.core.AbstractVerticle.start(AbstractVerticle.java:43)
	at io.vertx.core.Verticle.start(Verticle.java:66)
	at io.vertx.core.impl.DeploymentManager.lambda$doDeploy$8(DeploymentManager.java:556)
	at io.vertx.core.impl.ContextImpl.executeTask(ContextImpl.java:369)
	at io.vertx.core.impl.EventLoopContext.lambda$executeAsync$0(EventLoopContext.java:38)
	at io.netty.util.concurrent.AbstractEventExecutor.safeExecute$$$capture(AbstractEventExecutor.java:163)
	at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java)
	at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:416)
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:515)
	at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:918)
	at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
	at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.ClassNotFoundException: org.glassfish.jersey.internal.RuntimeDelegateImpl
	at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:264)
	at javax.ws.rs.ext.FactoryFinder.newInstance(FactoryFinder.java:87)
	at javax.ws.rs.ext.FactoryFinder.find(FactoryFinder.java:185)
	at javax.ws.rs.ext.RuntimeDelegate.findDelegate(RuntimeDelegate.java:112)
	... 21 more

[drejc]

As far as I can tell from the provided stack trace ... it seems like the registered writer has no media type assigned an it fails on a log statement:

at javax.ws.rs.core.MediaType.toString(MediaType.java:395)
	at java.lang.String.valueOf(String.java:2994)
	at java.lang.StringBuilder.append(StringBuilder.java:131)
	at com.zandero.rest.writer.WriterFactory.register(WriterFactory.java:158)
	at com.zandero.rest.writer.WriterFactory.register(WriterFactory.java:96)

Nevertheless I have tried to replicate this on my own as I see no problem with the response writer implementation and as usual it works on my machine.

So something must be problematic with the setup / or maybe a third library ... hard to tell.

Can you create a breakpoint at: com.zandero.rest.writer.WriterFactory.register(WriterFactory.java:96)
and check the values of type and writer variables?

[kevinstier]

The value of writer is Class demo.DefaultResponseWriter. The value of type is a MediaType with type "application", subtype "json" and paramaters is empty


[drejc]

This seem OK, can you debug to the point failing?

…

On Fri, 29 May 2020 at 14:16, kevinstier ***@***.***> wrote: The value of writer is Class demo.DefaultResponseWriter. The value of type is a MediaType with type "application", subtype "json" and paramaters is empty  — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#62 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AANSVF3JQOF2IPZF5CFPZVLRT6RTLANCNFSM4NNYEUXA> .

[kevinstier]

The log in the register method of WriterFactory prints MediaType in a String. This causes a call to toString() on MediaType. This method tries to get an instance for javax.ws.rs.ext.RuntimeDelegate with fallback class org.glassfish.jersey.internal.RuntimeDelegateImpl, but is unable to find both.

The same exception is thrown when I register the writer as:
RestRouter.getWriters().register(MediaType.APPLICATION_JSON_TYPE, DefaultResponseWriter.class);

Do you have an idea what can cause this problem?

[drejc]

Jap ... this is what I was assuming from the first stack trace ...

In my local project I see a reference to: org.glassfish.jersey.core:jersey-common:2.22.2
and I have the following test dependecy:

<dependency>
           <groupId>org.glassfish.jersey.core</groupId>
           <artifactId>jersey-common</artifactId>
           <version>${version.glassfish}</version>
           <scope>test</scope>
       </dependency>

I assume this is the problem.

I will fix this so the project will not be dependent on this library (it probably is not needed). In the mean time if you add this dependency it will probably work.

[kevinstier]

This solved the problem! Thank you