我不知道为什么我不能再启动我的vaadin 14应用程序了！有什么建议吗？

2021-07-13 16:41:49.657 ERROR 19384 --- [  restartedMain] o.a.c.c.C.[Tomcat].[localhost].[/]       : Exception sending context initialized event to listener instance of class [com.vaadin.flow.spring.VaadinServletContextInitializer$CompositeServletContextListener]

elemental.json.JsonException: Invalid literal: ""
    at elemental.json.impl.JsonTokenizer.getValueForLiteral(JsonTokenizer.java:310) ~[vaadin-shared-8.0.0.jar:8.0.0]
    at elemental.json.impl.JsonTokenizer.nextValue(JsonTokenizer.java:175) ~[vaadin-shared-8.0.0.jar:8.0.0]
    at elemental.json.impl.JreJsonFactory.parse(JreJsonFactory.java:64) ~[vaadin-shared-8.0.0.jar:8.0.0]
    at elemental.json.Json.parse(Json.java:53) ~[vaadin-shared-8.0.0.jar:8.0.0]
    at com.vaadin.flow.server.frontend.TaskInstallWebpackPlugins.generatePluginFiles(TaskInstallWebpackPlugins.java:127) ~[flow-server-2.6.3.jar:2.6.3]
    at com.vaadin.flow.server.frontend.TaskInstallWebpackPlugins.lambda$execute$0(TaskInstallWebpackPlugins.java:68) ~[flow-server-2.6.3.jar:2.6.3]
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1507) ~[na:na]
    at com.vaadin.flow.server.frontend.TaskInstallWebpackPlugins.execute(TaskInstallWebpackPlugins.java:66) ~[flow-server-2.6.3.jar:2.6.3]
    at com.vaadin.flow.server.frontend.NodeTasks.execute(NodeTasks.java:528) ~[flow-server-2.6.3.jar:2.6.3]
    at com.vaadin.flow.server.startup.DevModeInitializer.initDevModeHandler(DevModeInitializer.java:328) ~[flow-server-2.6.3.jar:2.6.3]
    at com.vaadin.flow.spring.VaadinServletContextInitializer$DevModeServletContextListener.contextInitialized(VaadinServletContextInitializer.java:440) ~[vaadin-spring-12.4.0.jar:na]
    at com.vaadin.flow.spring.VaadinServletContextInitializer$CompositeServletContextListener.lambda$contextInitialized$0(VaadinServletContextInitializer.java:180) ~[vaadin-spring-12.4.0.jar:na]
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1507) ~[na:na]
    at com.vaadin.flow.spring.VaadinServletContextInitializer$CompositeServletContextListener.contextInitialized(VaadinServletContextInitializer.java:180) ~[vaadin-spring-12.4.0.jar:na]
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4714) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5172) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1384) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1374) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
    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-9.0.45.jar:9.0.45]
    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-9.0.45.jar:9.0.45]
    at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:843) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1384) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1374) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
    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-9.0.45.jar:9.0.45]
    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-9.0.45.jar:9.0.45]
    at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:262) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
    at org.apache.catalina.core.StandardService.startInternal(StandardService.java:433) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
    at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:930) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
    at org.apache.catalina.startup.Tomcat.start(Tomcat.java:486) ~[tomcat-embed-core-9.0.45.jar:9.0.45]
    at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.initialize(TomcatWebServer.java:123) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.<init>(TomcatWebServer.java:104) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getTomcatWebServer(TomcatServletWebServerFactory.java:450) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getWebServer(TomcatServletWebServerFactory.java:199) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.createWebServer(ServletWebServerApplicationContext.java:181) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:159) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:577) ~[spring-context-5.3.6.jar:5.3.6]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:144) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:782) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:774) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:439) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:339) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1340) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1329) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.vaadin.example.Application.main(Application.java:19) ~[classes/:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
    at java.base/java.lang.reflect.Method.invoke(Method.java:567) ~[na:na]
    at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) ~[spring-boot-devtools-2.4.5.jar:2.4.5]

2021-07-13 16:42:01.757 ERROR 19384 --- [  restartedMain] o.apache.catalina.core.StandardContext   : One or more listeners failed to start. Full details will be found in the appropriate container log file
2021-07-13 16:43:14.043 ERROR 19384 --- [  restartedMain] o.apache.catalina.core.StandardContext   : Context [] startup failed due to previous errors
2021-07-13 16:43:14.862  INFO 19384 --- [  restartedMain] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2021-07-13 16:43:14.867  WARN 19384 --- [  restartedMain] 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
2021-07-13 16:43:14.877  INFO 19384 --- [  restartedMain] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2021-07-13 16:43:14.898 ERROR 19384 --- [  restartedMain] 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:162) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:577) ~[spring-context-5.3.6.jar:5.3.6]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:144) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:782) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:774) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:439) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:339) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1340) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1329) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.vaadin.example.Application.main(Application.java:19) ~[classes/:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
    at java.base/java.lang.reflect.Method.invoke(Method.java:567) ~[na:na]
    at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) ~[spring-boot-devtools-2.4.5.jar:2.4.5]
Caused by: org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat
    at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.initialize(TomcatWebServer.java:142) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.<init>(TomcatWebServer.java:104) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getTomcatWebServer(TomcatServletWebServerFactory.java:450) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getWebServer(TomcatServletWebServerFactory.java:199) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.createWebServer(ServletWebServerApplicationContext.java:181) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:159) ~[spring-boot-2.4.5.jar:2.4.5]
    ... 14 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:187) ~[spring-boot-2.4.5.jar:2.4.5]
    at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.initialize(TomcatWebServer.java:126) ~[spring-boot-2.4.5.jar:2.4.5]
    ... 19 common frames omitted