Error on start of Spring Boot Application (Vaadin)

Question

I tried to change port of Spring Boot application, activated Vaadin PRO, run in Eclipse/PowerShell, run in debug and without debug... I have node.js 12.16.1 (includes npm 6.13.4) installed too. I always get an error: java.lang.RuntimeException: Unable to initialize Vaadin DevModeHandler

:: Spring Boot ::        (v2.2.4.RELEASE)

2020-03-16 07:34:43.681  INFO 12284 --- [           main] s.q.myapp.ui.MyAppWebApplication   : Starting MyAppWebApplication on luigi10 with PID 12284 (C:\Workspaces\myapp\myapp\myapp-web\target\classes started by luigi.k in C:\Workspaces\myapp\myapp\myapp-web)
2020-03-16 07:34:43.684  INFO 12284 --- [           main] s.q.myapp.ui.MyAppWebApplication   : No active profile set, falling back to default profiles: default
2020-03-16 07:34:44.734  INFO 12284 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8082 (http)
2020-03-16 07:34:44.744  INFO 12284 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2020-03-16 07:34:44.745  INFO 12284 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.30]
2020-03-16 07:34:44.936  INFO 12284 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2020-03-16 07:34:44.936  INFO 12284 --- [           main] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1210 ms
2020-03-16 07:34:47.109  INFO 12284 --- [           main] c.v.f.s.VaadinServletContextInitializer  : Search for subclasses and classes with annotations took 1 seconds
2020-03-16 07:34:47.112  INFO 12284 --- [           main] c.v.f.server.startup.DevModeInitializer  : Starting dev-mode updaters in C:\Workspaces\myapp\myapp\myapp-web folder.
2020-03-16 07:34:47.141  INFO 12284 --- [           main] dev-updater                              : Visited 122 classes. Took 19 ms.
2020-03-16 07:34:47.156  INFO 12284 --- [           main] dev-updater                              : Skipping `npm install`.
2020-03-16 07:34:47.156  INFO 12284 --- [           main] dev-updater                              : Copying frontend resources from jar files ...
2020-03-16 07:34:47.219  INFO 12284 --- [           main] dev-updater                              : Visited 12 resources. Took 63 ms.
2020-03-16 07:34:47.286  INFO 12284 --- [           main] dev-updater                              : Updated C:\Workspaces\myapp\myapp\myapp-web\target\frontend\generated-flow-imports.js
2020-03-16 07:34:49.562  INFO 12284 --- [           main] dev-webpack                              : Starting webpack-dev-server, port: 57479 dir: C:\Workspaces\myapp\myapp\myapp-web
2020-03-16 07:34:49.577  INFO 12284 --- [           main] dev-webpack                              : Running webpack to compile frontend resources. This may take a moment, please stand by...
2020-03-16 07:34:50.406 ERROR 12284 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Exception sending context initialized event to listener instance of class [com.vaadin.flow.spring.VaadinServletContextInitializer$DevModeServletContextListener]

java.lang.RuntimeException: Unable to initialize Vaadin DevModeHandler
        at com.vaadin.flow.spring.VaadinServletContextInitializer$DevModeServletContextListener.contextInitialized(VaadinServletContextInitializer.java:347) ~[vaadin-spring-12.1.2.jar:na]
        at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4683) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
        at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5146) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
        at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1384) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
        at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1374) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
        at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[na:na]
        at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
        at java.base/java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:140) ~[na:na]
        at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:909) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
        at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:841) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
        at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1384) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
        at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1374) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
        at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[na:na]
        at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
        at java.base/java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:140) ~[na:na]
        at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:909) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
        at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:262) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
        at org.apache.catalina.core.StandardService.startInternal(StandardService.java:421) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
        at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:930) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
        at org.apache.catalina.startup.Tomcat.start(Tomcat.java:459) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
        at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.initialize(TomcatWebServer.java:107) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.<init>(TomcatWebServer.java:88) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getTomcatWebServer(TomcatServletWebServerFactory.java:438) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getWebServer(TomcatServletWebServerFactory.java:191) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.createWebServer(ServletWebServerApplicationContext.java:180) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:153) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:544) ~[spring-context-5.2.3.RELEASE.jar:5.2.3.RELEASE]
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at com.comp.myapp.ui.MyAppWebApplication.main(MyAppWebApplication.java:10) ~[classes/:na]
Caused by: javax.servlet.ServletException: java.lang.IllegalStateException: Webpack exited prematurely
        at com.vaadin.flow.server.startup.DevModeInitializer.initDevModeHandler(DevModeInitializer.java:301) ~[flow-server-2.1.5.jar:2.1.5]
        at com.vaadin.flow.spring.VaadinServletContextInitializer$DevModeServletContextListener.contextInitialized(VaadinServletContextInitializer.java:344) ~[vaadin-spring-12.1.2.jar:na]
        ... 38 common frames omitted
Caused by: java.lang.IllegalStateException: Webpack exited prematurely
        at com.vaadin.flow.server.DevModeHandler.<init>(DevModeHandler.java:202) ~[flow-server-2.1.5.jar:2.1.5]
        at com.vaadin.flow.server.DevModeHandler.createInstance(DevModeHandler.java:299) ~[flow-server-2.1.5.jar:2.1.5]
        at com.vaadin.flow.server.DevModeHandler.start(DevModeHandler.java:249) ~[flow-server-2.1.5.jar:2.1.5]
        at com.vaadin.flow.server.DevModeHandler.start(DevModeHandler.java:226) ~[flow-server-2.1.5.jar:2.1.5]
        at com.vaadin.flow.server.startup.DevModeInitializer.initDevModeHandler(DevModeInitializer.java:297) ~[flow-server-2.1.5.jar:2.1.5]
        ... 39 common frames omitted

2020-03-16 07:34:50.444 ERROR 12284 --- [           main] o.apache.catalina.core.StandardContext   : One or more listeners failed to start. Full details will be found in the appropriate container log file
2020-03-16 07:34:50.445 ERROR 12284 --- [           main] o.apache.catalina.core.StandardContext   : Context [] startup failed due to previous errors
2020-03-16 07:34:50.453  WARN 12284 --- [           main] o.a.c.loader.WebappClassLoaderBase       : The web application [ROOT] appears to have started a thread named [Thread-1] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 [email protected]/java.net.PlainSocketImpl.accept0(Native Method)
 [email protected]/java.net.PlainSocketImpl.socketAccept(PlainSocketImpl.java:159)
 [email protected]/java.net.AbstractPlainSocketImpl.accept(AbstractPlainSocketImpl.java:458)
 [email protected]/java.net.ServerSocket.implAccept(ServerSocket.java:551)
 [email protected]/java.net.ServerSocket.accept(ServerSocket.java:519)
 app//com.vaadin.flow.server.DevServerWatchDog$WatchDogServer.run(DevServerWatchDog.java:58)
 [email protected]/java.lang.Thread.run(Thread.java:834)
2020-03-16 07:34:50.669  INFO 12284 --- [           main] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2020-03-16 07:34:50.675  WARN 12284 --- [           main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.context.ApplicationContextException: Unable to start web server; nested exception is org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat
2020-03-16 07:34:50.684  INFO 12284 --- [           main] ConditionEvaluationReportLoggingListener :

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2020-03-16 07:34:50.693 ERROR 12284 --- [           main] o.s.boot.SpringApplication               : Application run failed

org.springframework.context.ApplicationContextException: Unable to start web server; nested exception is org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:156) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:544) ~[spring-context-5.2.3.RELEASE.jar:5.2.3.RELEASE]
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at com.comp.myapp.ui.MyAppWebApplication.main(MyAppWebApplication.java:10) ~[classes/:na]
Caused by: org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat
        at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.initialize(TomcatWebServer.java:126) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.<init>(TomcatWebServer.java:88) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getTomcatWebServer(TomcatServletWebServerFactory.java:438) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getWebServer(TomcatServletWebServerFactory.java:191) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.createWebServer(ServletWebServerApplicationContext.java:180) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:153) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        ... 8 common frames omitted
Caused by: java.lang.IllegalStateException: StandardEngine[Tomcat].StandardHost[localhost].TomcatEmbeddedContext[] failed to start
        at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.rethrowDeferredStartupExceptions(TomcatWebServer.java:171) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.initialize(TomcatWebServer.java:110) ~[spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
        ... 13 common frames omitted

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.2.4.RELEASE</version>
            <relativePath /> <!-- lookup parent from repository -->
        </parent>
        <groupId>com.corp</groupId>
        <artifactId>myapp-web</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <name>myapp-web</name>
        <description>WEB for MyApp</description>

        <properties>
            <java.version>11</java.version>
            <vaadin.version>14.1.17</vaadin.version>
        </properties>
        <repositories>
            <repository>
                <id>central</id>
                <url>https://repo.maven.apache.org/maven2</url>
                <snapshots>
                    <enabled>false</enabled>
                </snapshots>
            </repository>
            <repository>
                <id>vaadin-addons</id>
                <url>https://maven.vaadin.com/vaadin-addons</url>
                <snapshots>
                    <enabled>false</enabled>
                </snapshots>
            </repository>
        </repositories>
        <dependencies>
            <dependency>
                <groupId>com.vaadin</groupId>
                <artifactId>vaadin-crud-flow</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            <dependency>
                <groupId>com.vaadin</groupId>
                <artifactId>vaadin-spring-boot-starter</artifactId>
            </dependency>

            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
                <exclusions>
                    <exclusion>
                        <groupId>org.junit.vintage</groupId>
                        <artifactId>junit-vintage-engine</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
            <dependency>
                <groupId>com.vaadin</groupId>
                <artifactId>vaadin</artifactId>
                <exclusions>
                    <exclusion>
                        <groupId>com.vaadin.webjar</groupId>
                        <artifactId>*</artifactId>
                    </exclusion>
                    <exclusion>
                        <groupId>org.webjars.bowergithub.insites</groupId>
                        <artifactId>*</artifactId>
                    </exclusion>
                    <exclusion>
                        <groupId>org.webjars.bowergithub.polymer</groupId>
                        <artifactId>*</artifactId>
                    </exclusion>
                    <exclusion>
                        <groupId>org.webjars.bowergithub.polymerelements</groupId>
                        <artifactId>*</artifactId>
                    </exclusion>
                    <exclusion>
                        <groupId>org.webjars.bowergithub.vaadin</groupId>
                        <artifactId>*</artifactId>
                    </exclusion>
                    <exclusion>
                        <groupId>org.webjars.bowergithub.webcomponents</groupId>
                        <artifactId>*</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
        </dependencies>

        <dependencyManagement>
            <dependencies>
                <dependency>
                    <groupId>com.vaadin</groupId>
                    <artifactId>vaadin-bom</artifactId>
                    <version>${vaadin.version}</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
            </dependencies>
        </dependencyManagement>

        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
            </plugins>
        </build>
    </project>

The solution, that worked for me: I had node_modules folder checkout from GIT. I deleted all modules from folder node_modules and file package-lock.json too. Then I ran Spring Boot application and automatically started 'npm install' and generated new modules. Application was starting without error.

Answer 1

Run mvn clean install. This is a basic of work with Vaadin. If you have any problem with Vaadin at first rebuild the project.