奇怪的NullPointerException Maven的資源 - 插件

Question

大約一天兩次，我們得到我們構建一個NullPointerException：

[06:44:23]: [ERROR] Failed to execute goal org.apache.maven.plugins:maven-resources-plugin:2.5:resources (default-resources) on project spring-lib: Execution default-resources of goal org.apache.maven.plugins:maven-resources-plugin:2.5:resources failed. NullPointerException -> [Help 1] 
[06:44:23]: org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-resources-plugin:2.5:resources (default-resources) on project spring-lib: Execution default-resources of goal org.apache.maven.plugins:maven-resources-plugin:2.5:resources failed. 
[06:44:23]: at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:225) 
[06:44:23]: at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153) 
[06:44:23]: at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145) 
[06:44:23]: at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:84) 
[06:44:23]: at org.apache.maven.lifecycle.internal.LifecycleThreadedBuilder$1.call(LifecycleThreadedBuilder.java:167) 
[06:44:23]: at org.apache.maven.lifecycle.internal.LifecycleThreadedBuilder$1.call(LifecycleThreadedBuilder.java:164) 
[06:44:23]: at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303) 
[06:44:23]: at java.util.concurrent.FutureTask.run(FutureTask.java:138) 
[06:44:23]: at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441) 
[06:44:23]: at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303) 
[06:44:23]: at java.util.concurrent.FutureTask.run(FutureTask.java:138) 
[06:44:23]: at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) 
[06:44:23]: at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) 
[06:44:23]: at java.lang.Thread.run(Thread.java:619) 
[06:44:23]: Caused by: org.apache.maven.plugin.PluginExecutionException: Execution default-resources of goal org.apache.maven.plugins:maven-resources-plugin:2.5:resources failed. 
[06:44:23]: at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:110) 
[06:44:23]: at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:209) 
[06:44:23]: ... 13 more 
[06:44:23]: Caused by: java.lang.NullPointerException 
[06:44:23]: at java.util.ArrayList.<init>(ArrayList.java:131) 
[06:44:23]: at org.apache.maven.shared.filtering.DefaultMavenResourcesFiltering.filteredFileExtension(DefaultMavenResourcesFiltering.java:115) 
[06:44:23]: at org.apache.maven.shared.filtering.DefaultMavenResourcesFiltering.filterResources(DefaultMavenResourcesFiltering.java:264) 
[06:44:23]: at org.apache.maven.plugin.resources.ResourcesMojo.execute(ResourcesMojo.java:310) 
[06:44:23]: at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:101) 
[06:44:23]: ... 14 more 

這都在隨機時間，以及未來建設不會失敗。

我已經搜索了這個故障，沒有發現任何東西。我有這種直覺，認爲這可能是由maven-resources-plugin中的併發問題引起的。

我們得到這個錯誤與maven資源插件2.4.3，現在與2.5。我們的Maven版本是3.0.3。

我們用下面的參數執行上的TeamCity構建：

Goals: install 
Additional Maven command line parameters: -T 2C -e -P!releasex,integration 
-Dmaven.test.failure.ignore=true -Dmaven.test.error.ignore=true 
-Dmaven.test.haltafterfailure=false -Dmaven.junit.timeout=1000000 
-DwarProject.packaging=jar 

任何形式的解決此問題的幫助表示讚賞。

Answer 1

嘗試運行與-X maven並分析調試輸出。這可能有幫助。至少對我來說，它經常這樣做。

編輯：這是有問題的現貨：

113 publicboolean filteredFileExtension( String fileName, List userNonFilteredFileExtensions)
114 {
115  List nonFilteredFileExtensions = newArrayList ( getDefaultNonFilteredFileExtensions());

getDefault ..返回null。你有沒有改變nonFilteredExts？因爲它們默認填充在這裏：

63 // ------------------------------------------------
64 // Plexus lifecycle
65 // ------------------------------------------------
66 publicvoid initialize()
67  throwsInitializationException
68 {
69  // jpg,jpeg,gif,bmp,png
70  this.defaultNonFilteredFileExtensions = newArrayList (5);
71  this.defaultNonFilteredFileExtensions. add ("jpg");
72  this.defaultNonFilteredFileExtensions. add ("jpeg");
73  this.defaultNonFilteredFileExtensions. add ("gif");
74  this.defaultNonFilteredFileExtensions. add ("bmp");
75  this.defaultNonFilteredFileExtensions. add ("png");
76 } 

由於您正在並行構建，所以這可能是競爭條件。你應該真的在MRESOURCES提出一個問題。