[ERROR] Failed to execute goal com.vaadin:vaadin-maven-plugin:24.6.0:prepare-frontend (prepare-frontend) on project xxx-runtime: null: MojoFailureException: InvocationTargetException: Could not execute prepare-frontend goal. 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 null
Please run maven with ‘-X’ flag. There should be more information about the error in the logs.
One potential issue could be a JVM mistmatch. For example JVM used to run maven may be older than the one used by the IDE to compile classes
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$13 (QueryFunction.java:89)
at org.reflections.Reflections.get (Reflections.java:365)
at org.reflections.Reflections.getTypesAnnotatedWith (Reflections.java:403)
at com.vaadin.flow.server.scanner.ReflectionsClassFinder.getAnnotatedClasses (ReflectionsClassFinder.java:91)
at com.vaadin.flow.server.frontend.scanner.ClassFinder$CachedClassFinder.lambda$getAnnotatedClasses$0 (ClassFinder.java:154)
at java.util.HashMap.computeIfAbsent (HashMap.java:1220)
at com.vaadin.flow.server.frontend.scanner.ClassFinder$CachedClassFinder.getAnnotatedClasses (ClassFinder.java:153)
at com.vaadin.flow.server.frontend.scanner.FullDependenciesScanner.collectScripts (FullDependenciesScanner.java:327)
at com.vaadin.flow.server.frontend.scanner.FullDependenciesScanner.<init> (FullDependenciesScanner.java:162)
at com.vaadin.flow.server.frontend.scanner.FullDependenciesScanner.<init> (FullDependenciesScanner.java:110)
at com.vaadin.flow.server.frontend.scanner.FrontendDependenciesScanner$FrontendDependenciesScannerFactory.createScanner (FrontendDependenciesScanner.java:103)
at com.vaadin.flow.server.frontend.scanner.FrontendDependenciesScanner$FrontendDependenciesScannerFactory.createScanner (FrontendDependenciesScanner.java:115)
at com.vaadin.flow.server.frontend.NodeTasks.<init> (NodeTasks.java:123)
at com.vaadin.flow.plugin.base.BuildFrontendUtil.prepareFrontend (BuildFrontendUtil.java:181)
at com.vaadin.flow.plugin.maven.PrepareFrontendMojo.executeInternal (PrepareFrontendMojo.java:56)
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:569)
at com.vaadin.flow.plugin.maven.FlowModeAbstractMojo.execute (FlowModeAbstractMojo.java:306)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:126)
at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute2 (MojoExecutor.java:328)
at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute (MojoExecutor.java:316)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:212)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:174)
at org.apache.maven.lifecycle.internal.MojoExecutor.access$000 (MojoExecutor.java:75)
at org.apache.maven.lifecycle.internal.MojoExecutor$1.run (MojoExecutor.java:162)
at org.apache.maven.plugin.DefaultMojosExecutionStrategy.execute (DefaultMojosExecutionStrategy.java:39)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:159)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:105)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:73)
at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:53)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:118)
at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:261)
at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:173)
at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:101)
at org.apache.maven.cli.MavenCli.execute (MavenCli.java:906)
at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:283)
at org.apache.maven.cli.MavenCli.main (MavenCli.java:206)
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:569)
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)
I run the build from the command line
Can you post the full log?
after cleaning all up, the frontend build works now, thanks
Now I have another problem, i have a Polymer js component which is not displayed anymore after automatically converting it to Lit template (with the recommended plugin). Is there anywhere a migration description page from Polymer components to Lit?