尝试Run Vaadin 8.1 app under Java 9 prerelease in IntelliJ 2017.2.2，我能够使用fresh project构建vaadinjavanine.war，并使用Jetty Server托管相同的主机。
我最终试图将产生的战争部署到tomcat服务器。但是，在tomcat服务器启动期间，出现以下异常：
21-Aug-2017 22:53:38.830 SEVERE [localhost-startStop-1] org.apache.catalina.startup.ContextConfig.processAnnotationsFile Unable to process file [/Library/Tomcat/apache-tomcat-8.0.22/webapps/vaadinjavanine/WEB-INF/classes/module-info.class] for annotations
org.apache.tomcat.util.bcel.classfile.ClassFormatException: Invalid byte tag in constant pool: 19
at org.apache.tomcat.util.bcel.classfile.Constant.readConstant(Constant.java:97)
at org.apache.tomcat.util.bcel.classfile.ConstantPool.<init>(ConstantPool.java:55)
at org.apache.tomcat.util.bcel.classfile.ClassParser.readConstantPool(ClassParser.java:177)
at org.apache.tomcat.util.bcel.classfile.ClassParser.parse(ClassParser.java:85)
at org.apache.catalina.startup.ContextConfig.processAnnotationsStream(ContextConfig.java:2011)
at org.apache.catalina.startup.ContextConfig.processAnnotationsFile(ContextConfig.java:1994)
at org.apache.catalina.startup.ContextConfig.processAnnotationsFile(ContextConfig.java:1988)
at org.apache.catalina.startup.ContextConfig.processAnnotationsUrl(ContextConfig.java:1939)
at org.apache.catalina.startup.ContextConfig.processAnnotations(ContextConfig.java:1897)
at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1149)
at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:771)
at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:305)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5066)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:725)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:701)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:717)
at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:945)
at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1768)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
21-Aug-2017 22:53:38.980 SEVERE [localhost-startStop-1] org.apache.catalina.core.ContainerBase.addChildInternal ContainerBase.addChild: start:
org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/vaadinjavanine]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:725)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:701)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:717)
at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:945)
at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1768)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.UnsupportedClassVersionError: nullpointer/MyUI$MyUIServlet has been compiled by a more recent version of the Java Runtime (class file version 53.0), this version of the Java Runtime only recognizes class file versions up to 52.0 (unable to load class nullpointer.MyUI$MyUIServlet)
at org.apache.catalina.loader.WebappClassLoaderBase.findClassInternal(WebappClassLoaderBase.java:2476)
at org.apache.catalina.loader.WebappClassLoaderBase.findClass(WebappClassLoaderBase.java:854)
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1274)
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1157)
at org.atmosphere.util.IOUtils.isAtmosphere(IOUtils.java:381)
at org.atmosphere.cpr.ContainerInitializer.onStartup(ContainerInitializer.java:58)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5156)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
... 10 more
21-Aug-2017 22:53:38.981 SEVERE [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployWAR Error deploying web application archive /Library/Tomcat/apache-tomcat-8.0.22/webapps/vaadinjavanine.war
java.lang.IllegalStateException: ContainerBase.addChild: start: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/vaadinjavanine]]
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:728)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:701)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:717)
at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:945)
at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1768)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
该异常指出无法处理从Java9的
module-info.class生成的module-info.java。有办法解决吗？还是这实际上意味着tomcat尚未准备好使用Java9模块？注意：作为Tomcat的新手，我尚未自定义任何设置。让我知道，是否可以共享其他信息以获取更多信息。
最佳答案
我不是Tomcat专家，但是看起来模块描述符不是最严重的问题。接下来的异常包含以下块：
由以下原因引起：java.lang.UnsupportedClassVersionError：nullpointer/MyUI$MyUIServlet已由Java Runtime的最新版本（类文件版本53.0）编译，此版本的Java Runtime仅可识别52.0以下的类文件版本（无法加载类）
这看起来就像您在Java 8（类文件版本52）上运行Tomcat，而您的代码是使用Java 9（类文件版本53）进行编译的。
确保在Java 9上运行Tomcat。此外，您可能需要尝试early access build of Tomcat 9，这对于Java 9兼容性是必需的。