[Question] "ERROR SendableResponse" when running demo

[vtran5]

When I tried to run the Leshan server - client demo, I got an error: "ERROR SendableResponse - Exception while calling the reponse sent callback". It happens whenever the client register/update registration, even though the client's log says the registration update succeed. The full server's log of the error is below:

ERROR SendableResponse - Exception while calling the reponse sent callback
java.lang.reflect.InaccessibleObjectException: Unable to make private java.util.Collections$EmptyMap() accessible: module java.base does not "opens java.util" to unnamed module @dc9876b
at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:354)
at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:297)
at java.base/java.lang.reflect.Constructor.checkCanSetAccessible(Constructor.java:188)
at java.base/java.lang.reflect.Constructor.setAccessible(Constructor.java:181)
at com.google.gson.internal.reflect.UnsafeReflectionAccessor.makeAccessible(UnsafeReflectionAccessor.java:44)
at com.google.gson.internal.ConstructorConstructor.newDefaultConstructor(ConstructorConstructor.java:103)
at com.google.gson.internal.ConstructorConstructor.get(ConstructorConstructor.java:85)
at com.google.gson.internal.bind.MapTypeAdapterFactory.create(MapTypeAdapterFactory.java:127)
at com.google.gson.Gson.getAdapter(Gson.java:489)
at com.google.gson.Gson.toJson(Gson.java:727)
at com.google.gson.Gson.toJsonTree(Gson.java:628)
at com.google.gson.Gson.toJsonTree(Gson.java:607)
at com.google.gson.internal.bind.TreeTypeAdapter$GsonContextImpl.serialize(TreeTypeAdapter.java:155)
at org.eclipse.leshan.server.demo.servlet.json.RegistrationSerializer.serialize(RegistrationSerializer.java:52)
at org.eclipse.leshan.server.demo.servlet.json.RegistrationSerializer.serialize(RegistrationSerializer.java:28)
at com.google.gson.internal.bind.TreeTypeAdapter.write(TreeTypeAdapter.java:81)
at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:69)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.write(ReflectiveTypeAdapterFactory.java:127)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.write(ReflectiveTypeAdapterFactory.java:245)
at com.google.gson.Gson.toJson(Gson.java:735)
at com.google.gson.Gson.toJson(Gson.java:714)
at com.google.gson.Gson.toJson(Gson.java:669)
at com.google.gson.Gson.toJson(Gson.java:649)
at org.eclipse.leshan.server.demo.servlet.EventServlet$1.updated(EventServlet.java:94)
at org.eclipse.leshan.server.registration.RegistrationServiceImpl.fireUpdated(RegistrationServiceImpl.java:87)
at org.eclipse.leshan.server.registration.RegistrationHandler$2.run(RegistrationHandler.java:119)
at org.eclipse.leshan.core.response.SendableResponse.sent(SendableResponse.java:47)
at org.eclipse.leshan.server.californium.registration.RegisterResource.handleUpdate(RegisterResource.java:220)
at org.eclipse.leshan.server.californium.registration.RegisterResource.handlePOST(RegisterResource.java:98)
at org.eclipse.californium.core.CoapResource.handleRequest(CoapResource.java:227)
at org.eclipse.leshan.core.californium.LwM2mCoapResource.handleRequest(LwM2mCoapResource.java:51)
at org.eclipse.californium.core.server.ServerMessageDeliverer.deliverRequest(ServerMessageDeliverer.java:106)
at org.eclipse.californium.core.network.stack.BaseCoapStack$StackTopAdapter.receiveRequest(BaseCoapStack.java:204)
at org.eclipse.californium.core.network.stack.AbstractLayer.receiveRequest(AbstractLayer.java:84)
at org.eclipse.californium.core.network.stack.AbstractLayer.receiveRequest(AbstractLayer.java:84)
at org.eclipse.californium.core.network.stack.BlockwiseLayer.receiveRequest(BlockwiseLayer.java:413)
at org.eclipse.californium.core.network.stack.ReliabilityLayer.receiveRequest(ReliabilityLayer.java:276)
at org.eclipse.californium.core.network.stack.AbstractLayer.receiveRequest(AbstractLayer.java:84)
at org.eclipse.californium.core.network.stack.BaseCoapStack.receiveRequest(BaseCoapStack.java:137)
at org.eclipse.californium.core.network.CoapEndpoint$1.receiveRequest(CoapEndpoint.java:309)
at org.eclipse.californium.core.network.UdpMatcher$2.run(UdpMatcher.java:270)
at org.eclipse.californium.elements.util.SerialExecutor$1.run(SerialExecutor.java:289)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
at java.base/java.lang.Thread.run(Thread.java:833)

I compile and run the code at tag 1.3.2. My java version is:

java version "17.0.1" 2021-10-19 LTS
Java(TM) SE Runtime Environment (build 17.0.1+12-LTS-39)
Java HotSpot(TM) 64-Bit Server VM (build 17.0.1+12-LTS-39, mixed mode, sharing)

Maven version is:

Apache Maven 3.8.4 (9b656c72d54e5bacbed989b64718c159fe39b537)
Maven home: C:\Maven\apache-maven-3.8.4
Java version: 17.0.1, vendor: Oracle Corporation, runtime: C:\Program Files\Java\jdk-17.0.1
Default locale: en_US, platform encoding: Cp1252
OS name: "windows 10", version: "10.0", arch: "amd64", family: "windows"

My two commands to run the server demo and client demo are:
java -jar leshan-server-demo-1.3.2-jar-with-dependencies.jar
java -jar leshan-client-demo-1.3.2-jar-with-dependencies.jar

For what it's worth, the demo runs fine on my laptop with version v2.x (master branch).

Any help would be appreciated, thank you!

[sbernard31]

This looks like #1099

[vtran5]

Thank you! It actually is the same issue.