Estou tentando usar o Google App Engine para aplicativos baseados em Spring simples com maven. Eu descobri que há um arquétipo de maven disponível para esse tipo de aplicativo da web (sem mola, mas isso eu posso adicionar sozinho): Maven GAE.

Então usei o seguinte comando:

mvn archetype:generate -DarchetypeGroupId=net.kindleit -DarchetypeArtifactId=gae-archetype-jsp -DgroupId=com.example -DartifactId=form -DarchetypeRepository=http://maven-gae-plugin.googlecode.com/svn/repository 

No entanto, quando eu tentei usar "mvn gae: run" ele não funciona e eu não sei como resolver esse requisito ausente:

[INFO] BUILD FAILURE
    [INFO] ------------------------------------------------------------------------
    [INFO] Total time: 7.444s
    [INFO] Finished at: Sat Mar 02 21:04:22 CET 2013
    [INFO] Final Memory: 6M/15M
    [INFO] ------------------------------------------------------------------------
    [ERROR] Failed to execute goal net.kindleit:maven-gae-plugin:0.9.5:run (default-cli) on project form: Execution default-cli of goal net.kindleit:maven-gae-plugin:0.9.5:run failed: Plugin net.kindleit:maven-gae-plugin:0.9.5 or one of its dependencies could not be resolved: Failed to collect dependencies for net.kindleit:maven-gae-plugin:jar:0.9.5 (): Failed to read artifact descriptor for net.kindleit:gae-runtime:pom:1.7.5: Failure to find net.kindleit:maven-gae-parent:pom:0.9.6-SNAPSHOT in http://download.java.net/maven/2/ was cached in the local repository, resolution will not be reattempted until the update interval of maven2-repository.dev.java.net has elapsed or updates are forced -> [Help 1]
    org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal net.kindleit:maven-gae-plugin:0.9.5:run (default-cli) on project form: Execution default-cli of goal net.kindleit:maven-gae-plugin:0.9.5:run failed: Plugin net.kindleit:maven-gae-plugin:0.9.5 or one of its dependencies could not be resolved: Failed to collect dependencies for net.kindleit:maven-gae-plugin:jar:0.9.5 ()
        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:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        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-cli of goal net.kindleit:maven-gae-plugin:0.9.5:run failed: Plugin net.kindleit:maven-gae-plugin:0.9.5 or one of its dependencies could not be resolved: Failed to collect dependencies for net.kindleit:maven-gae-plugin:jar:0.9.5 ()
        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 net.kindleit:maven-gae-plugin:0.9.5 or one of its dependencies could not be resolved: Failed to collect dependencies for net.kindleit:maven-gae-plugin:jar:0.9.5 ()
        at org.apache.maven.plugin.internal.DefaultPluginDependenciesResolver.resolve(DefaultPluginDependenciesResolver.java:211)
        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.collection.DependencyCollectionException: Failed to collect dependencies for net.kindleit:maven-gae-plugin:jar:0.9.5 ()
        at org.sonatype.aether.impl.internal.DefaultDependencyCollector.collectDependencies(DefaultDependencyCollector.java:258)
        at org.sonatype.aether.impl.internal.DefaultRepositorySystem.collectDependencies(DefaultRepositorySystem.java:308)
        at org.apache.maven.plugin.internal.DefaultPluginDependenciesResolver.resolve(DefaultPluginDependenciesResolver.java:199)
        ... 24 more
    Caused by: org.sonatype.aether.resolution.ArtifactDescriptorException: Failed to read artifact descriptor for net.kindleit:gae-runtime:pom:1.7.5
        at org.apache.maven.repository.internal.DefaultArtifactDescriptorReader.loadPom(DefaultArtifactDescriptorReader.java:331)
        at org.apache.maven.repository.internal.DefaultArtifactDescriptorReader.readArtifactDescriptor(DefaultArtifactDescriptorReader.java:186)
        at org.sonatype.aether.impl.internal.DefaultDependencyCollector.process(DefaultDependencyCollector.java:412)
        at org.sonatype.aether.impl.internal.DefaultDependencyCollector.collectDependencies(DefaultDependencyCollector.java:240)
        ... 26 more
    Caused by: org.apache.maven.model.resolution.UnresolvableModelException: Failure to find net.kindleit:maven-gae-parent:pom:0.9.6-SNAPSHOT in http://download.java.net/maven/2/ was cached in the local repository, resolution will not be reattempted until the update interval of maven2-repository.dev.java.net has elapsed or updates are forced
        at org.apache.maven.repository.internal.DefaultModelResolver.resolveModel(DefaultModelResolver.java:126)
        at org.apache.maven.model.building.DefaultModelBuilder.readParentExternally(DefaultModelBuilder.java:813)
        at org.apache.maven.model.building.DefaultModelBuilder.readParent(DefaultModelBuilder.java:664)
        at org.apache.maven.model.building.DefaultModelBuilder.build(DefaultModelBuilder.java:310)
        at org.apache.maven.model.building.DefaultModelBuilder.build(DefaultModelBuilder.java:232)
        at org.apache.maven.repository.internal.DefaultArtifactDescriptorReader.loadPom(DefaultArtifactDescriptorReader.java:322)
        ... 29 more
    Caused by: org.sonatype.aether.resolution.ArtifactResolutionException: Failure to find net.kindleit:maven-gae-parent:pom:0.9.6-SNAPSHOT in http://download.java.net/maven/2/ was cached in the local repository, resolution will not be reattempted until the update interval of maven2-repository.dev.java.net has elapsed or updates are forced
        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.DefaultArtifactResolver.resolveArtifact(DefaultArtifactResolver.java:193)
        at org.apache.maven.repository.internal.DefaultModelResolver.resolveModel(DefaultModelResolver.java:122)
        ... 34 more
    Caused by: org.sonatype.aether.transfer.ArtifactNotFoundException: Failure to find net.kindleit:maven-gae-parent:pom:0.9.6-SNAPSHOT in http://download.java.net/maven/2/ was cached in the local repository, resolution will not be reattempted until the update interval of maven2-repository.dev.java.net has elapsed or updates are forced
        at org.sonatype.aether.impl.internal.DefaultUpdateCheckManager.newException(DefaultUpdateCheckManager.java:230)
        at org.sonatype.aether.impl.internal.DefaultUpdateCheckManager.checkArtifact(DefaultUpdateCheckManager.java:204)
        at org.sonatype.aether.impl.internal.DefaultArtifactResolver.resolve(DefaultArtifactResolver.java:427)
        ... 37 more

Pode-se acrescentar que tentei usar diferentes versões do maven-gae-plugin, mas sem sucesso ....