Testing an archetype

[jsfan3]

Hello,
I created a sample project with:

mvn archetype:generate -DarchetypeGroupId=com.vertispan.j2cl.archetypes \
-DarchetypeArtifactId=j2cl-archetype-simple \
-DarchetypeVersion=0.22.0 \
-DgroupId=com.galga.j2cl.taskmanager \
-DartifactId=j2cl-task-manager \
-Dversion=1.0-SNAPSHOT \
-Dmodule=MyJ2CLApp

Which mvn command do I use to convert from Java to JavaScript and which do I use to run tests?

Also, is Java 11 required?
I have noted these lines in the pom.xml:

    <maven.compiler.target>11</maven.compiler.target>
    <maven.compiler.source>11</maven.compiler.source>

[niloc132]

After you generate from an archetype, you can build and run test with mvn verify. That will result in a .war file (as well as the exploded war directory). This is documented at https://github.com/Vertispan/j2clmavenplugin/tree/main/j2cl-archetypes/j2cl-archetype-simple along with steps for development, to have the code be built automatically as you edit.

Java 11 or greater is required, our current version of closure-compiler mandates it.

[jsfan3]

Thank you, I read the instructions and did some experiments.

On my machine, mvn j2cl:build takes 21 seconds and mvn verify takes 51 seconds. I measured both times with j2cl-archetype-simple. This is a bit much, but I don't need to produce a war file, so mvn j2cl:build is sufficient (assuming I copy the produced js file into the web-app folder, which is easy to do by adding instructions in the pom.xml).

Anyway, to reduce the waiting time, using mvn jetty:run with mvn j2cl:watch seems like a good idea. The problem is that I am using Java 21. mvn j2cl:build and mvn j2cl:watch work fine with Java 21, but mvn jetty:run does not. The error is java.lang.IllegalArgumentException: Unsupported class file major version 65. Is there any way to make it work? This is the log:

francesco@asusrog:~/J2CL/j2cl-task-manager$ mvn jetty:run
[INFO] Scanning for projects...
[INFO] 
[INFO] ----------< com.baeldung.j2cl.taskmanager:j2cl-task-manager >-----------
[INFO] Building j2cl-task-manager 1.0-SNAPSHOT
[INFO] --------------------------------[ war ]---------------------------------
[INFO] 
[INFO] >>> jetty-maven-plugin:9.4.44.v20210927:run (default-cli) > test-compile @ j2cl-task-manager >>>
[INFO] 
[INFO] --- maven-resources-plugin:3.3.1:resources (default-resources) @ j2cl-task-manager ---
[WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory /home/francesco/J2CL/j2cl-task-manager/src/main/resources
[INFO] 
[INFO] --- maven-resources-plugin:3.3.1:copy-resources (copy-resources) @ j2cl-task-manager ---
[WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 1 resource from target/j2cl-task-manager-1.0-SNAPSHOT/j2cl-task-manager to src/main/webapp/js
[INFO] 
[INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ j2cl-task-manager ---
[INFO] Nothing to compile - all classes are up to date
[INFO] 
[INFO] --- maven-resources-plugin:3.3.1:testResources (default-testResources) @ j2cl-task-manager ---
[WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory /home/francesco/J2CL/j2cl-task-manager/src/test/resources
[INFO] 
[INFO] --- maven-compiler-plugin:3.8.1:testCompile (default-testCompile) @ j2cl-task-manager ---
[INFO] Nothing to compile - all classes are up to date
[INFO] 
[INFO] <<< jetty-maven-plugin:9.4.44.v20210927:run (default-cli) < test-compile @ j2cl-task-manager <<<
[INFO] 
[INFO] 
[INFO] --- jetty-maven-plugin:9.4.44.v20210927:run (default-cli) @ j2cl-task-manager ---
[INFO] Logging initialized @1937ms to org.eclipse.jetty.util.log.Slf4jLog
[INFO] webAppSourceDirectory not set. Trying src/main/webapp
[INFO] Reload Mechanic: automatic
[INFO] nonBlocking:false
[INFO] Classes = /home/francesco/J2CL/j2cl-task-manager/target/classes
[INFO] Configuring Jetty for project: j2cl-task-manager
[INFO] Context path = /
[INFO] Tmp directory = /home/francesco/J2CL/j2cl-task-manager/target/tmp
[INFO] Web defaults = org/eclipse/jetty/webapp/webdefault.xml
[INFO] Web overrides =  none
[INFO] web.xml file = null
[INFO] Webapp directory = /home/francesco/J2CL/j2cl-task-manager/src/main/webapp
[INFO] jetty-9.4.44.v20210927; built: 2021-09-27T23:02:44.612Z; git: 8da83308eeca865e495e53ef315a249d63ba9332; jvm 21.0.6+7-Ubuntu-124.04.1
[WARNING] com.baeldung.j2cl.taskmanager.MyJ2CLApp scanned from multiple locations: file:///home/francesco/J2CL/j2cl-task-manager/target/j2cl-task-manager-1.0-SNAPSHOT/WEB-INF/classes/com/baeldung/j2cl/taskmanager/MyJ2CLApp.class, file:///home/francesco/J2CL/j2cl-task-manager/target/classes/com/baeldung/j2cl/taskmanager/MyJ2CLApp.class
[WARNING] com.google.gwt.core.client.UnsafeNativeLong scanned from multiple locations: jar:file:///home/francesco/.m2/repository/com/google/jsinterop/base/1.0.0/base-1.0.0.jar!/com/google/gwt/core/client/UnsafeNativeLong.class, jar:file:///home/francesco/J2CL/j2cl-task-manager/target/j2cl-task-manager-1.0-SNAPSHOT/WEB-INF/lib/base-1.0.0.jar!/com/google/gwt/core/client/UnsafeNativeLong.class
[WARNING] jsinterop.base.Any scanned from multiple locations: jar:file:///home/francesco/J2CL/j2cl-task-manager/target/j2cl-task-manager-1.0-SNAPSHOT/WEB-INF/lib/base-1.0.0.jar!/jsinterop/base/Any.class, jar:file:///home/francesco/.m2/repository/com/google/jsinterop/base/1.0.0/base-1.0.0.jar!/jsinterop/base/Any.class

[... In total, there are 1154 warnings of the same type ...]

[INFO] Scanning elapsed time=271ms
[WARNING] Failed startup of context o.e.j.m.p.JettyWebAppContext@3050ac2f{/,[file:///home/francesco/J2CL/j2cl-task-manager/src/main/webapp/, file:///home/francesco/J2CL/j2cl-task-manager/target/j2cl-task-manager-1.0-SNAPSHOT/],UNAVAILABLE}{[file:///home/francesco/J2CL/j2cl-task-manager/src/main/webapp/, file:///home/francesco/J2CL/j2cl-task-manager/target/j2cl-task-manager-1.0-SNAPSHOT/]}
org.eclipse.jetty.util.MultiException: Multiple exceptions
    at org.eclipse.jetty.util.MultiException.ifExceptionThrow (MultiException.java:122)
    at org.eclipse.jetty.annotations.AnnotationConfiguration.scanForAnnotations (AnnotationConfiguration.java:492)
    at org.eclipse.jetty.annotations.AnnotationConfiguration.configure (AnnotationConfiguration.java:346)
    at org.eclipse.jetty.webapp.WebAppContext.configure (WebAppContext.java:498)
    at org.eclipse.jetty.webapp.WebAppContext.startContext (WebAppContext.java:1409)
    at org.eclipse.jetty.server.handler.ContextHandler.doStart (ContextHandler.java:910)
    at org.eclipse.jetty.servlet.ServletContextHandler.doStart (ServletContextHandler.java:288)
    at org.eclipse.jetty.webapp.WebAppContext.doStart (WebAppContext.java:524)
    at org.eclipse.jetty.maven.plugin.JettyWebAppContext.doStart (JettyWebAppContext.java:397)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start (AbstractLifeCycle.java:73)
    at org.eclipse.jetty.util.component.ContainerLifeCycle.start (ContainerLifeCycle.java:169)
    at org.eclipse.jetty.util.component.ContainerLifeCycle.doStart (ContainerLifeCycle.java:117)
    at org.eclipse.jetty.server.handler.AbstractHandler.doStart (AbstractHandler.java:97)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start (AbstractLifeCycle.java:73)
    at org.eclipse.jetty.util.component.ContainerLifeCycle.start (ContainerLifeCycle.java:169)
    at org.eclipse.jetty.util.component.ContainerLifeCycle.doStart (ContainerLifeCycle.java:117)
    at org.eclipse.jetty.server.handler.AbstractHandler.doStart (AbstractHandler.java:97)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start (AbstractLifeCycle.java:73)
    at org.eclipse.jetty.util.component.ContainerLifeCycle.start (ContainerLifeCycle.java:169)
    at org.eclipse.jetty.server.Server.start (Server.java:423)
    at org.eclipse.jetty.util.component.ContainerLifeCycle.doStart (ContainerLifeCycle.java:110)
    at org.eclipse.jetty.server.handler.AbstractHandler.doStart (AbstractHandler.java:97)
    at org.eclipse.jetty.server.Server.doStart (Server.java:387)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start (AbstractLifeCycle.java:73)
    at org.eclipse.jetty.maven.plugin.AbstractJettyMojo.startJetty (AbstractJettyMojo.java:449)
    at org.eclipse.jetty.maven.plugin.AbstractJettyMojo.execute (AbstractJettyMojo.java:310)
    at org.eclipse.jetty.maven.plugin.JettyRunMojo.execute (JettyRunMojo.java:150)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:137)
    at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute2 (MojoExecutor.java:370)
    at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute (MojoExecutor.java:351)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:215)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:171)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:163)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:117)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:81)
    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:56)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:128)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:298)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192)
    at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105)
    at org.apache.maven.cli.MavenCli.execute (MavenCli.java:960)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:293)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:196)
    at jdk.internal.reflect.DirectMethodHandleAccessor.invoke (DirectMethodHandleAccessor.java:103)
    at java.lang.reflect.Method.invoke (Method.java:580)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:283)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:226)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:407)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:348)
Caused by: java.lang.RuntimeException: Error scanning file /home/francesco/J2CL/j2cl-task-manager/target/j2cl-task-manager-1.0-SNAPSHOT/WEB-INF/classes/com/baeldung/j2cl/taskmanager/MyJ2CLApp.class
    at org.eclipse.jetty.annotations.AnnotationParser.parseDir (AnnotationParser.java:741)
    at org.eclipse.jetty.annotations.AnnotationParser.parse (AnnotationParser.java:828)
    at org.eclipse.jetty.annotations.AnnotationConfiguration$ParserTask.call (AnnotationConfiguration.java:159)
    at org.eclipse.jetty.annotations.AnnotationConfiguration$1.run (AnnotationConfiguration.java:455)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob (QueuedThreadPool.java:883)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run (QueuedThreadPool.java:1034)
    at java.lang.Thread.run (Thread.java:1583)
Caused by: java.lang.IllegalArgumentException: Unsupported class file major version 65
    at org.objectweb.asm.ClassReader.<init> (ClassReader.java:199)
    at org.objectweb.asm.ClassReader.<init> (ClassReader.java:180)
    at org.objectweb.asm.ClassReader.<init> (ClassReader.java:166)
    at org.objectweb.asm.ClassReader.<init> (ClassReader.java:287)
    at org.eclipse.jetty.annotations.AnnotationParser.scanClass (AnnotationParser.java:932)
    at org.eclipse.jetty.annotations.AnnotationParser.parseDir (AnnotationParser.java:734)
    at org.eclipse.jetty.annotations.AnnotationParser.parse (AnnotationParser.java:828)
    at org.eclipse.jetty.annotations.AnnotationConfiguration$ParserTask.call (AnnotationConfiguration.java:159)
    at org.eclipse.jetty.annotations.AnnotationConfiguration$1.run (AnnotationConfiguration.java:455)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob (QueuedThreadPool.java:883)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run (QueuedThreadPool.java:1034)
    at java.lang.Thread.run (Thread.java:1583)
[INFO] Started ServerConnector@34a2d6e0{HTTP/1.1, (http/1.1)}{0.0.0.0:8080}
[INFO] Started @2530ms
[INFO] Started Jetty Server

[niloc132]

On my machine, mvn j2cl:build takes 21 seconds and mvn verify takes 51 seconds. I measured both times with j2cl-archetype-simple. This is a bit much, but I don't need to produce a war file, so mvn j2cl:build is sufficient (assuming I copy the produced js file into the web-app folder, which is easy to do by adding instructions in the pom.xml).

Neither is needed for development - a war file wouldn't make sense anyway if you're intending to run j2cl:watch. Just j2cl:build takes less time than verify because verify includes tests - consider skipping tests, but correctly run j2cl:build as part of the phases to avoid skipping some other goal or configuration by mistake. If you're new to maven, this is not the plugin to start learning it on.

Anyway, to reduce the waiting time, using mvn jetty:run with mvn j2cl:watch seems like a good idea. The problem is that I am using Java 21. mvn j2cl:build and mvn j2cl:watch work fine with Java 21, but mvn jetty:run does not. The error is java.lang.IllegalArgumentException: Unsupported class file major version 65. Is there any way to make it work? This is the log:

Be careful about running them "at the same time" - from a clean build there could be a race condition where j2cl:watch creates the base directory for its output after jetty:run has already tried to find it, failed, and crashed.

It looks like you are running Java 21, but using the version of Jetty that we baked into the example archetype. Pick a newer server if you want to support Java 21 bytecode, such as Jetty 12.

Note also that at this time, J2CL itself is stuck with a max of source from Java 11, and this plugin has an additional limitation keeping it at Java 8.