java 为什么服务器启动时“无法定义类”警告？

Why "Failed to define class" WARN from server startup?

提问by Fagner Brack

When I execute liquibase in JBoss I get the following WARN but everything is updated correctly:

当我在 JBoss 中执行 liquibase 时，我收到以下警告，但一切都已正确更新：

12:32:01,499 WARN  [org.jboss.modules] (ServerService Thread Pool -- 49) Failed to define class liquibase.sdk.watch.WatchCommand$DynamicContentHandler in Module "deployment.WebStories.war:main" from Service Module Loader: java.lang.LinkageError: Failed to link liquibase/sdk/watch/WatchCommand$DynamicContentHandler (Module "deployment.WebStories.war:main" from Service Module Loader)
    at org.jboss.modules.ModuleClassLoader.defineClass(ModuleClassLoader.java:407) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ModuleClassLoader.loadClassLocal(ModuleClassLoader.java:254) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ModuleClassLoader.loadClassLocal(ModuleClassLoader.java:73) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.Module.loadModuleClass(Module.java:518) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ModuleClassLoader.findClass(ModuleClassLoader.java:182) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ConcurrentClassLoader.performLoadClassUnchecked(ConcurrentClassLoader.java:468) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ConcurrentClassLoader.performLoadClassChecked(ConcurrentClassLoader.java:456) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ConcurrentClassLoader.performLoadClass(ConcurrentClassLoader.java:398) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ConcurrentClassLoader.loadClass(ConcurrentClassLoader.java:120) [jboss-modules.jar:1.2.0.CR1]
    at liquibase.servicelocator.DefaultPackageScanClassResolver.loadClass(DefaultPackageScanClassResolver.java:358) [liquibase-core-3.2.2.jar:]
    at liquibase.servicelocator.DefaultPackageScanClassResolver.loadImplementationsInJar(DefaultPackageScanClassResolver.java:406) [liquibase-core-3.2.2.jar:]
    at liquibase.servicelocator.DefaultPackageScanClassResolver.findAllClasses(DefaultPackageScanClassResolver.java:226) [liquibase-core-3.2.2.jar:]
    at liquibase.servicelocator.DefaultPackageScanClassResolver.find(DefaultPackageScanClassResolver.java:116) [liquibase-core-3.2.2.jar:]
    at liquibase.servicelocator.DefaultPackageScanClassResolver.findImplementations(DefaultPackageScanClassResolver.java:84) [liquibase-core-3.2.2.jar:]
    at liquibase.servicelocator.ServiceLocator.findClassesImpl(ServiceLocator.java:202) [liquibase-core-3.2.2.jar:]
    at liquibase.servicelocator.ServiceLocator.findClasses(ServiceLocator.java:177) [liquibase-core-3.2.2.jar:]
    at liquibase.database.DatabaseFactory.<init>(DatabaseFactory.java:25) [liquibase-core-3.2.2.jar:]
    at liquibase.database.DatabaseFactory.getInstance(DatabaseFactory.java:40) [liquibase-core-3.2.2.jar:]
    at liquibase.integration.servlet.LiquibaseServletListener.executeUpdate(LiquibaseServletListener.java:211) [liquibase-core-3.2.2.jar:]
    at liquibase.integration.servlet.LiquibaseServletListener.contextInitialized(LiquibaseServletListener.java:106) [liquibase-core-3.2.2.jar:]
    at org.apache.catalina.core.StandardContext.contextListenerStart(StandardContext.java:3339) [jbossweb-7.2.0.Final.jar:7.2.0.Final]
    at org.apache.catalina.core.StandardContext.start(StandardContext.java:3777) [jbossweb-7.2.0.Final.jar:7.2.0.Final]
    at org.jboss.as.web.deployment.WebDeploymentService.doStart(WebDeploymentService.java:156) [jboss-as-web-7.2.0.Alpha1-redhat-4.jar:7.2.0.Alpha1-redhat-4]
    at org.jboss.as.web.deployment.WebDeploymentService.access
package org.eclipse.jetty.server.handler;

/**
 * Workaround for this issues in liquibase.
 * http://stackoverflow.com/questions/26530677/why-failed-to-define-class-warn-from-server-startup.
 * https://liquibase.jira.com/browse/CORE-2024.
 *
 * @author cilap
 *
 */
public class AbstractHandler {

   /**
    * Trace to logfile the workaround.
    */
   public AbstractHandler() {
      System.err.println("Workaround for http://stackoverflow.com/questions    /26530677/why-failed-to-define-class-warn-from-server-startup and "
            + "https://liquibase.jira.com/browse/CORE-2024");
      System.err.println("please remove this from the repository as soon as the bug is fixed on liquibase.");
   }
}
0(WebDeploymentService.java:60) [jboss-as-web-7.2.0.Alpha1-redhat-4.jar:7.2.0.Alpha1-redhat-4]
    at org.jboss.as.web.deployment.WebDeploymentService.run(WebDeploymentService.java:93) [jboss-as-web-7.2.0.Alpha1-redhat-4.jar:7.2.0.Alpha1-redhat-4]
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) [rt.jar:1.7.0_11]
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334) [rt.jar:1.7.0_11]
    at java.util.concurrent.FutureTask.run(FutureTask.java:166) [rt.jar:1.7.0_11]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) [rt.jar:1.7.0_11]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) [rt.jar:1.7.0_11]
    at java.lang.Thread.run(Thread.java:722) [rt.jar:1.7.0_11]
    at org.jboss.threads.JBossThread.run(JBossThread.java:122)
Caused by: java.lang.NoClassDefFoundError: org/eclipse/jetty/server/handler/AbstractHandler
    at java.lang.ClassLoader.defineClass1(Native Method) [rt.jar:1.7.0_11]
    at java.lang.ClassLoader.defineClass(ClassLoader.java:791) [rt.jar:1.7.0_11]
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) [rt.jar:1.7.0_11]
    at org.jboss.modules.ModuleClassLoader.doDefineOrLoadClass(ModuleClassLoader.java:338) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ModuleClassLoader.defineClass(ModuleClassLoader.java:402) [jboss-modules.jar:1.2.0.CR1]
    ... 31 more
Caused by: java.lang.ClassNotFoundException: org.eclipse.jetty.server.handler.AbstractHandler from [Module "deployment.WebStories.war:main" from Service Module Loader]
    at org.jboss.modules.ModuleClassLoader.findClass(ModuleClassLoader.java:190) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ConcurrentClassLoader.performLoadClassUnchecked(ConcurrentClassLoader.java:468) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ConcurrentClassLoader.performLoadClassChecked(ConcurrentClassLoader.java:456) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ConcurrentClassLoader.performLoadClass(ConcurrentClassLoader.java:398) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ConcurrentClassLoader.loadClass(ConcurrentClassLoader.java:120) [jboss-modules.jar:1.2.0.CR1]
    ... 36 more

12:32:01,532 WARN  [org.jboss.modules] (ServerService Thread Pool -- 49) Failed to define class liquibase.sdk.supplier.database.AllDatabaseTypes in Module "deployment.WebStories.war:main" from Service Module Loader: java.lang.LinkageError: Failed to link liquibase/sdk/supplier/database/AllDatabaseTypes (Module "deployment.WebStories.war:main" from Service Module Loader)
    at org.jboss.modules.ModuleClassLoader.defineClass(ModuleClassLoader.java:407) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ModuleClassLoader.loadClassLocal(ModuleClassLoader.java:254) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ModuleClassLoader.loadClassLocal(ModuleClassLoader.java:73) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.Module.loadModuleClass(Module.java:518) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ModuleClassLoader.findClass(ModuleClassLoader.java:182) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ConcurrentClassLoader.performLoadClassUnchecked(ConcurrentClassLoader.java:468) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ConcurrentClassLoader.performLoadClassChecked(ConcurrentClassLoader.java:456) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ConcurrentClassLoader.performLoadClass(ConcurrentClassLoader.java:398) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ConcurrentClassLoader.loadClass(ConcurrentClassLoader.java:120) [jboss-modules.jar:1.2.0.CR1]
    at liquibase.servicelocator.DefaultPackageScanClassResolver.loadClass(DefaultPackageScanClassResolver.java:358) [liquibase-core-3.2.2.jar:]
    at liquibase.servicelocator.DefaultPackageScanClassResolver.loadImplementationsInJar(DefaultPackageScanClassResolver.java:406) [liquibase-core-3.2.2.jar:]
    at liquibase.servicelocator.DefaultPackageScanClassResolver.findAllClasses(DefaultPackageScanClassResolver.java:226) [liquibase-core-3.2.2.jar:]
    at liquibase.servicelocator.DefaultPackageScanClassResolver.find(DefaultPackageScanClassResolver.java:116) [liquibase-core-3.2.2.jar:]
    at liquibase.servicelocator.DefaultPackageScanClassResolver.findImplementations(DefaultPackageScanClassResolver.java:84) [liquibase-core-3.2.2.jar:]
    at liquibase.servicelocator.ServiceLocator.findClassesImpl(ServiceLocator.java:202) [liquibase-core-3.2.2.jar:]
    at liquibase.servicelocator.ServiceLocator.findClasses(ServiceLocator.java:177) [liquibase-core-3.2.2.jar:]
    at liquibase.database.DatabaseFactory.<init>(DatabaseFactory.java:25) [liquibase-core-3.2.2.jar:]
    at liquibase.database.DatabaseFactory.getInstance(DatabaseFactory.java:40) [liquibase-core-3.2.2.jar:]
    at liquibase.integration.servlet.LiquibaseServletListener.executeUpdate(LiquibaseServletListener.java:211) [liquibase-core-3.2.2.jar:]
    at liquibase.integration.servlet.LiquibaseServletListener.contextInitialized(LiquibaseServletListener.java:106) [liquibase-core-3.2.2.jar:]
    at org.apache.catalina.core.StandardContext.contextListenerStart(StandardContext.java:3339) [jbossweb-7.2.0.Final.jar:7.2.0.Final]
    at org.apache.catalina.core.StandardContext.start(StandardContext.java:3777) [jbossweb-7.2.0.Final.jar:7.2.0.Final]
    at org.jboss.as.web.deployment.WebDeploymentService.doStart(WebDeploymentService.java:156) [jboss-as-web-7.2.0.Alpha1-redhat-4.jar:7.2.0.Alpha1-redhat-4]
    at org.jboss.as.web.deployment.WebDeploymentService.access##代码##0(WebDeploymentService.java:60) [jboss-as-web-7.2.0.Alpha1-redhat-4.jar:7.2.0.Alpha1-redhat-4]
    at org.jboss.as.web.deployment.WebDeploymentService.run(WebDeploymentService.java:93) [jboss-as-web-7.2.0.Alpha1-redhat-4.jar:7.2.0.Alpha1-redhat-4]
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) [rt.jar:1.7.0_11]
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334) [rt.jar:1.7.0_11]
    at java.util.concurrent.FutureTask.run(FutureTask.java:166) [rt.jar:1.7.0_11]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) [rt.jar:1.7.0_11]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) [rt.jar:1.7.0_11]
    at java.lang.Thread.run(Thread.java:722) [rt.jar:1.7.0_11]
    at org.jboss.threads.JBossThread.run(JBossThread.java:122)
Caused by: java.lang.NoClassDefFoundError: org/junit/experimental/theories/ParameterSupplier
    at java.lang.ClassLoader.defineClass1(Native Method) [rt.jar:1.7.0_11]
    at java.lang.ClassLoader.defineClass(ClassLoader.java:791) [rt.jar:1.7.0_11]
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) [rt.jar:1.7.0_11]
    at org.jboss.modules.ModuleClassLoader.doDefineOrLoadClass(ModuleClassLoader.java:338) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ModuleClassLoader.defineClass(ModuleClassLoader.java:402) [jboss-modules.jar:1.2.0.CR1]
    ... 31 more
Caused by: java.lang.ClassNotFoundException: org.junit.experimental.theories.ParameterSupplier from [Module "deployment.WebStories.war:main" from Service Module Loader]
    at org.jboss.modules.ModuleClassLoader.findClass(ModuleClassLoader.java:190) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ConcurrentClassLoader.performLoadClassUnchecked(ConcurrentClassLoader.java:468) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ConcurrentClassLoader.performLoadClassChecked(ConcurrentClassLoader.java:456) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ConcurrentClassLoader.performLoadClass(ConcurrentClassLoader.java:398) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ConcurrentClassLoader.loadClass(ConcurrentClassLoader.java:120) [jboss-modules.jar:1.2.0.CR1]
    ... 36 more

12:32:01,546 WARN  [org.jboss.modules] (ServerService Thread Pool -- 49) Failed to define class liquibase.sdk.supplier.database.AllDatabases in Module "deployment.WebStories.war:main" from Service Module Loader: java.lang.LinkageError: Failed to link liquibase/sdk/supplier/database/AllDatabases (Module "deployment.WebStories.war:main" from Service Module Loader)
    at org.jboss.modules.ModuleClassLoader.defineClass(ModuleClassLoader.java:407) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ModuleClassLoader.loadClassLocal(ModuleClassLoader.java:254) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ModuleClassLoader.loadClassLocal(ModuleClassLoader.java:73) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.Module.loadModuleClass(Module.java:518) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ModuleClassLoader.findClass(ModuleClassLoader.java:182) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ConcurrentClassLoader.performLoadClassUnchecked(ConcurrentClassLoader.java:468) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ConcurrentClassLoader.performLoadClassChecked(ConcurrentClassLoader.java:456) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ConcurrentClassLoader.performLoadClass(ConcurrentClassLoader.java:398) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ConcurrentClassLoader.loadClass(ConcurrentClassLoader.java:120) [jboss-modules.jar:1.2.0.CR1]
    at liquibase.servicelocator.DefaultPackageScanClassResolver.loadClass(DefaultPackageScanClassResolver.java:358) [liquibase-core-3.2.2.jar:]
    at liquibase.servicelocator.DefaultPackageScanClassResolver.loadImplementationsInJar(DefaultPackageScanClassResolver.java:406) [liquibase-core-3.2.2.jar:]
    at liquibase.servicelocator.DefaultPackageScanClassResolver.findAllClasses(DefaultPackageScanClassResolver.java:226) [liquibase-core-3.2.2.jar:]
    at liquibase.servicelocator.DefaultPackageScanClassResolver.find(DefaultPackageScanClassResolver.java:116) [liquibase-core-3.2.2.jar:]
    at liquibase.servicelocator.DefaultPackageScanClassResolver.findImplementations(DefaultPackageScanClassResolver.java:84) [liquibase-core-3.2.2.jar:]
    at liquibase.servicelocator.ServiceLocator.findClassesImpl(ServiceLocator.java:202) [liquibase-core-3.2.2.jar:]
    at liquibase.servicelocator.ServiceLocator.findClasses(ServiceLocator.java:177) [liquibase-core-3.2.2.jar:]
    at liquibase.database.DatabaseFactory.<init>(DatabaseFactory.java:25) [liquibase-core-3.2.2.jar:]
    at liquibase.database.DatabaseFactory.getInstance(DatabaseFactory.java:40) [liquibase-core-3.2.2.jar:]
    at liquibase.integration.servlet.LiquibaseServletListener.executeUpdate(LiquibaseServletListener.java:211) [liquibase-core-3.2.2.jar:]
    at liquibase.integration.servlet.LiquibaseServletListener.contextInitialized(LiquibaseServletListener.java:106) [liquibase-core-3.2.2.jar:]
    at org.apache.catalina.core.StandardContext.contextListenerStart(StandardContext.java:3339) [jbossweb-7.2.0.Final.jar:7.2.0.Final]
    at org.apache.catalina.core.StandardContext.start(StandardContext.java:3777) [jbossweb-7.2.0.Final.jar:7.2.0.Final]
    at org.jboss.as.web.deployment.WebDeploymentService.doStart(WebDeploymentService.java:156) [jboss-as-web-7.2.0.Alpha1-redhat-4.jar:7.2.0.Alpha1-redhat-4]
    at org.jboss.as.web.deployment.WebDeploymentService.access##代码##0(WebDeploymentService.java:60) [jboss-as-web-7.2.0.Alpha1-redhat-4.jar:7.2.0.Alpha1-redhat-4]
    at org.jboss.as.web.deployment.WebDeploymentService.run(WebDeploymentService.java:93) [jboss-as-web-7.2.0.Alpha1-redhat-4.jar:7.2.0.Alpha1-redhat-4]
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) [rt.jar:1.7.0_11]
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334) [rt.jar:1.7.0_11]
    at java.util.concurrent.FutureTask.run(FutureTask.java:166) [rt.jar:1.7.0_11]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) [rt.jar:1.7.0_11]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) [rt.jar:1.7.0_11]
    at java.lang.Thread.run(Thread.java:722) [rt.jar:1.7.0_11]
    at org.jboss.threads.JBossThread.run(JBossThread.java:122)
Caused by: java.lang.NoClassDefFoundError: org/junit/experimental/theories/ParameterSupplier
    at java.lang.ClassLoader.defineClass1(Native Method) [rt.jar:1.7.0_11]
    at java.lang.ClassLoader.defineClass(ClassLoader.java:791) [rt.jar:1.7.0_11]
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) [rt.jar:1.7.0_11]
    at org.jboss.modules.ModuleClassLoader.doDefineOrLoadClass(ModuleClassLoader.java:338) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ModuleClassLoader.defineClass(ModuleClassLoader.java:402) [jboss-modules.jar:1.2.0.CR1]
    ... 31 more
Caused by: java.lang.ClassNotFoundException: org.junit.experimental.theories.ParameterSupplier from [Module "deployment.WebStories.war:main" from Service Module Loader]
    at org.jboss.modules.ModuleClassLoader.findClass(ModuleClassLoader.java:190) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ConcurrentClassLoader.performLoadClassUnchecked(ConcurrentClassLoader.java:468) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ConcurrentClassLoader.performLoadClassChecked(ConcurrentClassLoader.java:456) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ConcurrentClassLoader.performLoadClass(ConcurrentClassLoader.java:398) [jboss-modules.jar:1.2.0.CR1]
    at org.jboss.modules.ConcurrentClassLoader.loadClass(ConcurrentClassLoader.java:120) [jboss-modules.jar:1.2.0.CR1]
    ... 36 more

12:32:01,652 ERROR [stderr] (ServerService Thread Pool -- 49) INFO 23/10/14 12:32: liquibase: Successfully acquired change log lock

12:32:02,336 ERROR [stderr] (ServerService Thread Pool -- 49) INFO 23/10/14 12:32: liquibase: Reading from public.databasechangelog

12:32:02,383 ERROR [stderr] (ServerService Thread Pool -- 49) INFO 23/10/14 12:32: liquibase: Successfully released change log lock

Any stacktrace in the server startup is considered an error, despite it is marked as a WARN, INFO or NOTHING.

服务器启动中的任何堆栈跟踪都被视为错误，尽管它被标记为 WARN、INFO 或 NOTHING。

Why does that happen?
What can I do to remove this stacktrace from the server startup?

为什么会这样？
我该怎么做才能从服务器启动中删除此堆栈跟踪？

回答by Nathan Voxland

Liquibase internally scans your classpath using your classloader to find classes that may be Liquibase extensions. Part of that scanning is hitting a few classes that are bundled with the liquibase jar but are not part of the normal liquibase updateprocess.

Liquibase 使用类加载器在内部扫描您的类路径，以查找可能是 Liquibase 扩展的类。扫描的一部分是命中一些与 liquibase jar 捆绑在一起但不属于正常liquibase update过程的类。

In particular, it is checking code that displays the database and liquibase state that can be helpful in demos and troubleshooting and other code that can be used for testing extensions.

特别是，它正在检查显示数据库和 liquibase 状态的代码，这有助于演示和故障排除以及其他可用于测试扩展的代码。

These non-standard use classes reference additional dependencies such as jetty and junit and which are normally not available in production environments and so Liquibase expects some ClassNotFoundExceptions and DEBUG-level logs them, moves on, and updates correctly as you are seeing.

这些非标准使用类引用了额外的依赖项，例如 jetty 和 junit，它们通常在生产环境中不可用，因此 Liquibase 期望一些 ClassNotFoundExceptions 和 DEBUG 级别记录它们，继续前进，并如您所见地正确更新。

In your case, it appears that the JBoss classloader has an additional feature to log at WARN level any ClassNotFoundExceptions it runs into throwing it up the chain to the point that Liquibase ignores it.

在您的情况下，JBoss 类加载器似乎有一个附加功能，可以在 WARN 级别记录它运行到的任何 ClassNotFoundExceptions 将其向上抛出到 Liquibase 忽略它的程度。

A future release of Liquibase will better split between the "tools" codebase and the "standard" codebase, but for now your options would be:

Liquibase 的未来版本将更好地分为“工具”代码库和“标准”代码库，但现在您的选择是：

• Include the missing dependencies in your classpath (jetty and junit based in your stacktrace)
• Create enough of a stub class named the same as the referenced jetty and junit classes in order to make the class loader happy.
• Set the log level for "org.jboss.modules" to ERROR in order to not log WARN-level logs

• 在类路径中包含缺少的依赖项（基于堆栈跟踪的 jetty 和 junit）
• 创建足够多的存根类，其名称与引用的 jetty 和 junit 类相同，以使类加载器满意。
• 将“org.jboss.modules”的日志级别设置为 ERROR 以便不记录 WARN 级别的日志

回答by cilap

I have used this class, which very probably will notwork on jetty, but on all other servers (tomcat, jboss/wildfly, weblogic, websphere, glassfish, tomee, ...) I've tested it on tomcat and wildfly.

我已经使用这个类，它很可能将无法工作的码头，但在所有其他服务器（Tomcat的，JBoss的/ wildfly中，WebLogic，WebSphere中，GlassFish的，tomee，...）我已经测试了Tomcat和wildfly。

##代码##

This is not nice but it works.

这不是很好，但它有效。

Edit1:

编辑1：

The Classloader is searching for the Class org.eclipse.jetty.server.handler.AbstractHandlerSince we are not on the Jetty, the class cannot be found by the classloader.

类加载器正在搜索类org.eclipse.jetty.server.handler.AbstractHandler由于我们不在 Jetty 上，因此类加载器无法找到该类。

One option would be to add the jetty jar file into the tomcat or the wildfly, BUTthis will very probably cause issues on tomcat/wildfly, since they implement also expected interfaces and classes which both, Jetty and Wildfly/tomcat provide. To avoid this - until it is fixed by Liquibase - you have to provide the Classloader a dummy implementation of AbstractHandler. So the classloader is happy and finds the AbstractHandler and the WARN message is gone.

一个办法是到码头的jar文件添加到Tomcat或wildfly，但这个也很有可能导致在Tomcat / wildfly，因为他们实施也有望接口和两个类，码头和Wildfly / tomcat的提供问题。为了避免这种情况——直到它被 Liquibase 修复——你必须为 Classloader 提供一个 AbstractHandler 的虚拟实现。所以类加载器很高兴并找到了 AbstractHandler 并且 WARN 消息消失了。

As said this is not nice but is a workaround to get rid of the odd messages in the logfile and console. If we are lucky, liquibase may incorporate a fix for this minor bug in 3.4 or maybe in 4.0.

如前所述，这并不好，但它是一种摆脱日志文件和控制台中奇怪消息的解决方法。如果幸运的话，liquibase 可能会在 3.4 或 4.0 中修复这个小错误。