Vaadin-maven-plugin failed to build frontend after updating to Java 17

Question

After updating language version to Java 17 vaadin-maven-plugin fails to compile frontend due to reflection error.

Caused by: com.vaadin.flow.server.ExecutionFailedException: Error occured during goal execution: Cannot invoke "java.lang.Class.isInterface()" because the return value of "org.reflections.Reflections.forClass(String, java.lang.ClassLoader[])" is nullPlease run Maven with the -e switch (or Gradle with the --stacktrace switch), to learn the full stack trace.
    at com.vaadin.flow.plugin.base.BuildFrontendUtil.runNodeUpdater (BuildFrontendUtil.java:346)
    at com.vaadin.flow.plugin.maven.BuildFrontendMojo.execute (BuildFrontendMojo.java:100)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:137)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:210)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:156)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:148)
    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:305)
    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:957)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:289)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:193)
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:77)
    at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke (Method.java:568)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:282)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:225)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:406)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:347)
    at org.codehaus.classworlds.Launcher.main (Launcher.java:47)
Caused by: java.lang.NullPointerException: Cannot invoke "java.lang.Class.isInterface()" because the return value of "org.reflections.Reflections.forClass(String, java.lang.ClassLoader[])" is null
    at org.reflections.Reflections.lambda$getTypesAnnotatedWith$12 (Reflections.java:405)
    at java.util.stream.ReferencePipeline$2$1.accept (ReferencePipeline.java:178)
    at java.util.Iterator.forEachRemaining (Iterator.java:133)
    at java.util.Spliterators$IteratorSpliterator.forEachRemaining (Spliterators.java:1845)
    at java.util.stream.AbstractPipeline.copyInto (AbstractPipeline.java:509)
    at java.util.stream.AbstractPipeline.wrapAndCopyInto (AbstractPipeline.java:499)
    at java.util.stream.ReduceOps$ReduceOp.evaluateSequential (ReduceOps.java:921)
    at java.util.stream.AbstractPipeline.evaluate (AbstractPipeline.java:234)
    at java.util.stream.ReferencePipeline.collect (ReferencePipeline.java:682)
    at org.reflections.util.QueryFunction.lambda$filter$3 (QueryFunction.java:32)
    at org.reflections.util.QueryFunction.lambda$add$9 (QueryFunction.java:66)
    at org.reflections.util.QueryFunction.lambda$add$9 (QueryFunction.java:66)
    at org.reflections.util.QueryFunction.lambda$asClass$13 (QueryFunction.java:89)
    at org.reflections.Reflections.get (Reflections.java:365)
    at org.reflections.Reflections.getTypesAnnotatedWith (Reflections.java:403)
    at com.vaadin.flow.server.scanner.ReflectionsClassFinder.getAnnotatedClasses (ReflectionsClassFinder.java:65)
    at com.vaadin.flow.server.frontend.scanner.ClassFinder$CachedClassFinder.lambda$getAnnotatedClasses$0 (ClassFinder.java:148)
    at java.util.HashMap.computeIfAbsent (HashMap.java:1220)
    at com.vaadin.flow.server.frontend.scanner.ClassFinder$CachedClassFinder.getAnnotatedClasses (ClassFinder.java:147)
    at com.vaadin.flow.server.frontend.scanner.FrontendDependencies.computeEndpoints (FrontendDependencies.java:270)
    at com.vaadin.flow.server.frontend.scanner.FrontendDependencies.<init> (FrontendDependencies.java:130)
    at com.vaadin.flow.server.frontend.scanner.FrontendDependenciesScanner$FrontendDependenciesScannerFactory.createScanner (FrontendDependenciesScanner.java:130)
    at com.vaadin.flow.server.frontend.scanner.FrontendDependenciesScanner$FrontendDependenciesScannerFactory.createScanner (FrontendDependenciesScanner.java:92)
    at com.vaadin.flow.server.frontend.NodeTasks.<init> (NodeTasks.java:727)
    at com.vaadin.flow.server.frontend.NodeTasks.<init> (NodeTasks.java:55)
    at com.vaadin.flow.server.frontend.NodeTasks$Builder.build (NodeTasks.java:236)
    at com.vaadin.flow.plugin.base.BuildFrontendUtil.runNodeUpdater (BuildFrontendUtil.java:340)
    at com.vaadin.flow.plugin.maven.BuildFrontendMojo.execute (BuildFrontendMojo.java:100)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:137)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:210)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:156)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:148)
    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:305)
    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:957)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:289)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:193)
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:77)
    at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke (Method.java:568)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:282)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:225)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:406)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:347)
    at org.codehaus.classworlds.Launcher.main (Launcher.java:47)

It looks like Vaadin Maven Plugin internal error.

Versions:

Java: OpenJDK 17.0.3

Vaadin: 23.0.5

Answer 1

This error occurs because of Preview features were in the source code, but I attempted to compile it without --enable-preview.

Adding the --enable-preview flag to the main process seems to solve the issue (eg export MAVEN_OPTS="$MAVEN_OPTS --enable-preview")

My bad.