对于一些多模块maven项目，我们在使用maven 3.0.4时遇到以下异常：
[ERROR] Failed to execute goal org.codehaus.mojo:gwt-maven-plugin:1.3.2.google:resources (default) on project genericapi: Execution default of goal org.codehaus.mojo:gwt-maven-plugin:1.3.2.google:resources failed: Plugin org.codehaus.mojo:gwt-maven-plugin:1.3.2.google or one of its dependencies could not be resolved: Could not find artifact dom4j:dom4j:jar:1.6.1 in gwt-plugin-repo (http://google-web-toolkit.googlecode.com/svn/2.1.0.M3/gwt/maven) -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.codehaus.mojo:gwt-maven-plugin:1.3.2.google:resources (default) on project genericapi: Execution default of goal org.codehaus.mojo:gwt-maven-plugin:1.3.2.google:resources failed: Plugin org.codehaus.mojo:gwt-maven-plugin:1.3.2.google or one of its dependencies could not be resolved: Could not find artifact dom4j:dom4j:jar:1.6.1 in gwt-plugin-repo (http://google-web-toolkit.googlecode.com/svn/2.1.0.M3/gwt/maven)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:225)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:84)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:59)
at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBuild(LifecycleStarter.java:183)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:161)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:320)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:156)
at org.apache.maven.cli.MavenCli.execute(MavenCli.java:537)
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:196)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:141)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:616)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:290)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:230)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:409)
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:352)
Caused by: org.apache.maven.plugin.PluginExecutionException: Execution default of goal org.codehaus.mojo:gwt-maven-plugin:1.3.2.google:resources failed: Plugin org.codehaus.mojo:gwt-maven-plugin:1.3.2.google or one of its dependencies could not be resolved: Could not find artifact dom4j:dom4j:jar:1.6.1 in gwt-plugin-repo (http://google-web-toolkit.googlecode.com/svn/2.1.0.M3/gwt/maven)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:82)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:209)
... 19 more
Caused by: org.apache.maven.plugin.PluginResolutionException: Plugin org.codehaus.mojo:gwt-maven-plugin:1.3.2.google or one of its dependencies could not be resolved: Could not find artifact dom4j:dom4j:jar:1.6.1 in gwt-plugin-repo (http://google-web-toolkit.googlecode.com/svn/2.1.0.M3/gwt/maven)
at org.apache.maven.plugin.internal.DefaultPluginDependenciesResolver.resolve(DefaultPluginDependenciesResolver.java:215)
at org.apache.maven.plugin.internal.DefaultMavenPluginManager.createPluginRealm(DefaultMavenPluginManager.java:353)
at org.apache.maven.plugin.internal.DefaultMavenPluginManager.setupPluginRealm(DefaultMavenPluginManager.java:321)
at org.apache.maven.plugin.DefaultBuildPluginManager.getPluginRealm(DefaultBuildPluginManager.java:175)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:78)
... 20 more
Caused by: org.sonatype.aether.resolution.ArtifactResolutionException: Could not find artifact dom4j:dom4j:jar:1.6.1 in gwt-plugin-repo (http://google-web-toolkit.googlecode.com/svn/2.1.0.M3/gwt/maven)
at org.sonatype.aether.impl.internal.DefaultArtifactResolver.resolve(DefaultArtifactResolver.java:538)
at org.sonatype.aether.impl.internal.DefaultArtifactResolver.resolveArtifacts(DefaultArtifactResolver.java:216)
at org.sonatype.aether.impl.internal.DefaultRepositorySystem.resolveDependencies(DefaultRepositorySystem.java:358)
at org.apache.maven.plugin.internal.DefaultPluginDependenciesResolver.resolve(DefaultPluginDependenciesResolver.java:207)
... 24 more
Caused by: org.sonatype.aether.transfer.ArtifactNotFoundException: Could not find artifact dom4j:dom4j:jar:1.6.1 in gwt-plugin-repo (http://google-web-toolkit.googlecode.com/svn/2.1.0.M3/gwt/maven)
at org.sonatype.aether.connector.wagon.WagonRepositoryConnector$4.wrap(WagonRepositoryConnector.java:947)
at org.sonatype.aether.connector.wagon.WagonRepositoryConnector$4.wrap(WagonRepositoryConnector.java:941)
at org.sonatype.aether.connector.wagon.WagonRepositoryConnector$GetTask.run(WagonRepositoryConnector.java:669)
at org.sonatype.aether.util.concurrency.RunnableErrorForwarder$1.run(RunnableErrorForwarder.java:60)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:679)
[ERROR]
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/PluginResolutionException
[ERROR]
[ERROR] After correcting the problems, you can resume the build with the command
[ERROR] mvn <goals> -rf :genericapi
注意：我比较了mvn3.0.3 / mvn3.0.4的日志，它们看起来是相同的，唯一不同的是只发生在3.0.4的异常，
更多的说，我检查了maven trunk并将Aether从ver 1.13.1更改为1.12，一切正常！这意味着它可能是Aether 1.13及更高版本中引入的错误。
任何帮助都将受到高度赞赏！