NoClassDefFoundError for multi-module dependency in Vert.x reactive routes when using Maven quarkusDev

[wjtan]

Describe the bug
A multi-module maven project contains two submodules mod1 and mod2, where mod2 depends on mod1.
When running mod2 in dev mode, NoClassDefFoundError occurs for a route class from mod1.

The error does not occur when the application is built with mvn package and run with java -jar mod2/target/mod2-0.0.1-SNAPSHOT-runner.jar.

Expected behavior
The application should work no matter if it is run in dev mode or not.

Actual behavior
If the application is started with mvn compile quarkus:dev -pl mod2, an internal server error is returned when a request is made to a route in mod1. Both the log and the HTTP response contain a stacktrace:

2021-02-20 02:39:39,613 ERROR [io.qua.ver.htt.run.QuarkusErrorHandler] (vert.x-eventloop-thread-3) HTTP Request to /mod1/ failed, error id: d2ed3e7e-337e-4fcf-9c6e-eddc7944cecc-1: java.lang.NoClassDefFoundError: sg/wjtan/mod1/IndexPage
        at sg.wjtan.mod1.IndexPage_RouteHandler_index_279c3f7d45b3461bf7246354cb951cebf8120d77.invoke(IndexPage_RouteHandler_index_279c3f7d45b3461bf7246354cb951cebf8120d77.zig:104)
        at io.quarkus.vertx.web.runtime.RouteHandler.handle(RouteHandler.java:97)
        at io.quarkus.vertx.web.runtime.RouteHandler.handle(RouteHandler.java:22)
        at io.vertx.ext.web.impl.RouteState.handleContext(RouteState.java:1038)
        at io.vertx.ext.web.impl.RoutingContextImplBase.iterateNext(RoutingContextImplBase.java:101)
        at io.vertx.ext.web.impl.RoutingContextImpl.next(RoutingContextImpl.java:132)
        at io.quarkus.vertx.http.runtime.VertxHttpRecorder$17.handle(VertxHttpRecorder.java:1121)
        at io.quarkus.vertx.http.runtime.VertxHttpRecorder$17.handle(VertxHttpRecorder.java:1092)
        at io.vertx.ext.web.impl.RouteState.handleContext(RouteState.java:1038)
        at io.vertx.ext.web.impl.RoutingContextImplBase.iterateNext(RoutingContextImplBase.java:137)
        at io.vertx.ext.web.impl.RoutingContextImpl.next(RoutingContextImpl.java:132)
        at io.quarkus.vertx.http.runtime.VertxHttpRecorder$4.handle(VertxHttpRecorder.java:333)
        at io.quarkus.vertx.http.runtime.VertxHttpRecorder$4.handle(VertxHttpRecorder.java:311)
        at io.vertx.ext.web.impl.RouteState.handleContext(RouteState.java:1038)
        at io.vertx.ext.web.impl.RoutingContextImplBase.iterateNext(RoutingContextImplBase.java:137)
        at io.vertx.ext.web.impl.RoutingContextImpl.next(RoutingContextImpl.java:132)
        at io.quarkus.vertx.http.runtime.devmode.VertxHttpHotReplacementSetup$3.handle(VertxHttpHotReplacementSetup.java:86)
        at io.quarkus.vertx.http.runtime.devmode.VertxHttpHotReplacementSetup$3.handle(VertxHttpHotReplacementSetup.java:75)
        at io.vertx.core.impl.ContextImpl.lambda$null$0(ContextImpl.java:327)
        at io.vertx.core.impl.ContextImpl.executeTask(ContextImpl.java:366)
        at io.vertx.core.impl.EventLoopContext.lambda$executeAsync$0(EventLoopContext.java:38)
        at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:164)
        at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472)
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:500)
        at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
        at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.lang.ClassNotFoundException: sg.wjtan.mod1.IndexPage
        at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581)
        at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
        at io.quarkus.bootstrap.classloading.QuarkusClassLoader.loadClass(QuarkusClassLoader.java:428)
        at io.quarkus.bootstrap.classloading.QuarkusClassLoader.loadClass(QuarkusClassLoader.java:378)
        ... 28 more

To Reproduce

Steps to reproduce the behavior:

1. Fetch to sample project from https://github.com/wjtan/quarkus-multi-web
2. Compile the project mvn install
3. Start the application using mvn compile quarkus:dev -pl mod2
4. Open the URL http://localhost:8080/mod1

Environment (please complete the following information):

• Output of uname -a or ver: Windows 10 20H2
• Output of java -version: java 11.0.10 2021-01-19 LTS
• GraalVM version (if different from Java): n/a
• Quarkus version or git rev: 1.12.0.Final
• Build tool (ie. output of mvnw --version or gradlew --version): Maven 3.6.3

[quarkus-bot]

/cc @quarkusio/devtools