blocks|key|171985|text|我通过删除项目中的.settings文件夹和.project文件，然后重新导入项目来解决我的问题。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|171986|entityMap^0|9|9|M|8|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|M|8|@]|D|@]|E|$]]]|G|$]]

I solved mine by deleting the <code>.settings</code> folder and <code>.project</code> file in the project and then reimporting the project.

blocks|key|170739|text|我找到了用户Maneesh+Godbole在CodeRanch上找到的答案|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|170740|170741|blockquote|170742|170743|170744|Close+eclipse.|ordered-list-item|170745|Navigate+to+your“directory|170746|Restart+eclipse|170747|Import”folder|170748|确保操作系统上用于查看隐藏文件的设置已打开，并识别并删除.metadata+workspace|170749|170750|entityMap|0|LINK|mutability|MUTABLE|url|http://www.coderanch.com/t/632460/vc/Eclipse^0|6|F|M|9|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|14|8|@$9|15|A|16|B|C]]|D|@$9|17|A|18|1|19]]|E|$]]|$1|F|3|-4|5|6|7|1A|8|@]|D|@]|E|$]]|$1|G|3|-4|5|H|7|1B|8|@]|D|@]|E|$]]|$1|I|3|-4|5|6|7|1C|8|@]|D|@]|E|$]]|$1|J|3|-4|5|6|7|1D|8|@]|D|@]|E|$]]|$1|K|3|L|5|M|7|1E|8|@]|D|@]|E|$]]|$1|N|3|O|5|M|7|1F|8|@]|D|@]|E|$]]|$1|P|3|Q|5|M|7|1G|8|@]|D|@]|E|$]]|$1|R|3|S|5|M|7|1H|8|@]|D|@]|E|$]]|$1|T|3|U|5|M|7|1I|8|@]|D|@]|E|$]]|$1|V|3|-4|5|6|7|1J|8|@]|D|@]|E|$]]|$1|W|3|-4|5|6|7|1K|8|@]|D|@]|E|$]]]|X|$Y|$5|Z|10|11|E|$12|13]]]]

For me worked the answer I found on <a href="http://www.coderanch.com/t/632460/vc/Eclipse" rel="noreferrer" title="CodeRanch">CodeRanch</a>, by user Maneesh Godbole:

<blockquote>
 <ol>
 <li>Close eclipse.</li>
 <li>Navigate to your "workspace" folder</li>
 <li>Ensure the setting on your OS to view hidden files is turned on</li>
 <li>Identify and delete the .metadata directory</li>
 <li>Restart eclipse</li>
 <li>Import project </li>
 </ol>
</blockquote>

blocks|key|2775244|text|我在我的一个模块中也遇到了同样的问题。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2775245|在控制台/cmd中运行"mvn+eclipse:eclipse“为我解决了这个问题。|2775246|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

I've had the same problem in one of my modules.

Running "mvn eclipse:eclipse" in the console/cmd solved the problem for me.

blocks|key|172948|text|在这个问题的实例中，我们有pom.xml文件，其中特定于M2E的生命周期映射配置|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|172949|<pluginManagement>
++++<plugins>
++++++++<plugin>
++++++++++++<groupId>org.eclipse.m2e</groupId>
++++++++++++<artifactId>lifecycle-mapping</artifactId>
++++++++++++<version>1.0.0</version>
++++++++++++<configuration>
++++++++++++++++<lifecycleMappingMetadata>
...|code-block|syntax|javascript|172950|没有<version>1.0.0</version>部件。在执行Maven+->更新项目时，这会导致报告的NullPointerException没有堆栈跟踪。使用新导入时...对于现有的Maven项目，同样的异常也发生了，但堆栈跟踪使我找到了上面的问题。|172951|(这是随m2e+1.6.1.20150625-2338一起发布的版本2(4.4.2)。)|172952|entityMap^0|D|7|0|0|2|O|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@]|E|$]]|$1|M|3|N|5|6|7|X|8|@]|D|@]|E|$]]|$1|O|3|-4|5|6|7|Y|8|@]|D|@]|E|$]]]|P|$]]

In our instance of this problem, we had <code>pom.xml</code> files where the m2e-specific life cycle mapping configuration

<pre><code>&lt;pluginManagement&gt;
 &lt;plugins&gt;
 &lt;plugin&gt;
 &lt;groupId&gt;org.eclipse.m2e&lt;/groupId&gt;
 &lt;artifactId&gt;lifecycle-mapping&lt;/artifactId&gt;
 &lt;version&gt;1.0.0&lt;/version&gt;
 &lt;configuration&gt;
 &lt;lifecycleMappingMetadata&gt;
...
</code></pre>

did not have the <code>&lt;version&gt;1.0.0&lt;/version&gt;</code> part. When doing a Maven -> Update Project..., this causes the reported NullPointerException without a stack trace. When using a fresh Import... -> Existing Maven Projects, the same exception occurred, but with a stack trace that led me to find the above.

(This is with m2e 1.6.1.20150625-2338 in Eclipse Luna Service Release 2 (4.4.2).)

blocks|key|2988013|text|为了防止它对任何人有帮助，除了删除.settings和.project之外，我还必须删除.classpath和.factorypath，然后才能成功地将项目导入到Eclipse中。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2988014|entityMap^0|H|9|R|8|18|A|1J|C|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]|$9|M|A|N|B|C]|$9|O|A|P|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|G|$]]

In case it helps anyone, in addition to deleting <code>.settings</code> and <code>.project</code>, I had to delete <code>.classpath</code> and <code>.factorypath</code> before being able to import the project successfully into Eclipse.

blocks|key|174467|text|org.eclipse.m2e.core.prefs文件位于.settings文件夹中。如果你面临这样的问题|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|174468|An+internal+error+occurred+during:+"Updating+Maven+Project".+java.lang.NullPointerException|CODE|174469|从eclipse中删除该项目，然后在项目->中删除.settings文件夹&+.project文件，然后重新导入该项目。|174470|entityMap^0|0|Q|U|9|0|0|2J|0|P|9|13|8|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|R|8|@$9|S|A|T|B|H]]|D|@]|E|$]]|$1|I|3|J|5|6|7|U|8|@$9|V|A|W|B|C]|$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|K|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|L|$]]

org.eclipse.m2e.core.prefs file is in .settings folder. If you face the problem of 

<code>An internal error occurred during: "Updating Maven Project". java.lang.NullPointerException</code>

Delete the project from eclipse then by deleting the .settings folder &amp; .project file in the project -> then re-import the project.

blocks|key|2988049|text|上面的方法对我都不起作用。这也可能是由于eclipse工作区中存在循环依赖而引起的。因此，如果在您的工作区中的任何其他项目中存在任何其他错误，请尝试修复这些错误，然后这个问题就会消失。这就是我消除错误的方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2988050|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

None of the above methods worked for me. This might also arise due to the presence of circular dependency in your eclipse workspace. So if there are any other errors present in any of the other projects in your workspace, try to fix those and then this issue will be gone. This is how i eliminated the error.

blocks|key|170859|text|这对我很有帮助：Project+menu+->+Clean...+->+clean+all+projects|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|170860|entityMap^0|8|1A|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

This helped me: <code>Project menu -&gt; Clean... -&gt; clean all projects</code>

blocks|key|2775642|text|Eclipse有一个错误日志。在那里，您将看到完整的堆栈跟踪。在我的例子中，它似乎是由一个坏的jar文件和java.util.zip库结合在一起造成的，没有抛出适当的异常，只是抛出了一个NullPointerException。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2775643|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Eclipse has an error log. There you will see the complete stack trace. In my case it seems to be caused by a bad jar file combined with the java.util.zip libs not throwing a proper exception, just a NullPointerException.

blocks|key|174649|text|我使用的是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|174650|面向Web开发人员的Eclipse+Java+EE+IDE。|174651|版本:+Neon.3+Release+(4.6.3)+Build+:+20170314-1500|174652|对我来说，修复/技巧是删除~/.m2/repository中的本地存储库，以便移除本地依赖关系，并重新构建项目，其中新的依赖关系被拉下。|174653|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|L|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|M|8|@]|9|@]|A|$]]|$1|H|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|I|$]]

I'm using:

Eclipse Java EE IDE for Web Developers.

Version: Neon.3 Release (4.6.3)
Build id: 20170314-1500

The fix/trick for me was deleting my local repository in ~/.m2/repository in order to remove local dependencies and rebuilding my project in which fresh dependencies are pulled down.

blocks|key|174455|text|我也有同样的问题。这里的解决方案都不起作用。我不得不完全重新安装eclipse并创建一个新的工作区。然后它成功了！|type|unstyled|depth|inlineStyleRanges|entityRanges|data|174456|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

I had the same problem. None of the solutions here worked. I had to completely reinstall eclipse and make a new workspace. Then it worked!

blocks|key|2775410|text|我在多个项目和多个工作空间中遇到了同样的问题，我在网上找到的解决方案都不适合我。我使用的是STS，唯一有效的方法是进入我的STS目录，在STS.ini文件的顶部添加一个"-clean“。然后，您可以启动您的工作区并运行maven+clean，而不会出现错误。(您也可以从ini文件中删除-clean标记，这样它就不会在您每次启动它时进行清理)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2775411|希望这对某些人有帮助。|2775412|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

I had this same issue across multiple projects and multiple workspaces, none of the solutions I found online worked for me. I'm using STS and the only thing that worked was to go into my STS directory and add a "-clean" to the top of the STS.ini file. You can then start up your workspace and run maven clean without errors. (you can also remove the -clean tag from the ini file so it doesn't clean everytime you start it)

Hope this helps someone.

blocks|key|2775414|text|在我的例子中，根本问题是.settings文件夹中的文件冲突。因此，删除.settings文件夹本来可以解决Maven错误，但我希望保留一些本地配置文件。我解决了冲突，然后再次尝试Maven更新，它起作用了。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2775415|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

The root issue in my case was a file conflict in the .settings folder. So, deleting the .settings folder would have resolved the Maven error, but I wanted to keep some of my local configuration files. I resolved the conflict, then tried a Maven update again and it worked.

blocks|key|2988160|text|我也有同样的问题...最终的解决方案！|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2988161|下面是eclipse日志：|2988162|java.lang.NullPointerException
++++at+com.google.appengine.eclipse.wtp.maven.GaeRuntimeManager.getGaeRuntime(GaeRuntimeManager.java:85)
++++at+com.google.appengine.eclipse.wtp.maven.GaeRuntimeManager.ensureGaeRuntimeWithSdk(GaeRuntimeManager.java:55)
++++at+com.google.appengine.eclipse.wtp.maven.GaeFacetManager.addGaeFacet(GaeFacetManager.java:59)
++++at+com.google.appengine.eclipse.wtp.maven.GaeProjectConfigurator.configure(GaeProjectConfigurator.java:46)|code-block|syntax|javascript|2988163|..。它来自于"appengine+maven+wtp+plugin“，它试图获取GAE运行时的类型，但在这里似乎是空的(...getRuntimeType()+-->+NPE)：|2988164|请参见类com.google.appengine.eclipse.wtp.maven/GaeRuntimeManager.java|offset|length|2988165|++private+static+IRuntime+getGaeRuntime(String+sdkVersion)+{
++++IRuntime[]+runtimes+=+ServerCore.getRuntimes();
++++for+(IRuntime+runtime+:+runtimes)+{
++++++if+(runtime+!=+null+&&++**runtime.getRuntimeType()**.equals(GAE_RUNTIME_TYPE))+{|2988166|因此，如果您签入eclipse，Google+App+Engine是可见的，但是当您选择它时，您将看到没有与SDK相关联的SDK+...|2988167|📷|atomic|2988168|​|2988169|解决方案:截图上红色的+;-)|style|BOLD|2988170|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/gwt-plugins/gwt-eclipse-plugin/blob/master/plugins/com.google.appengine.eclipse.wtp.maven/src/com/google/appengine/eclipse/wtp/maven/GaeRuntimeManager.java|1|IMAGE|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/436fb9251b892f61139b2fec8e66bd9f.png|imageAlt^0|0|0|0|0|4|1P|0|0|0|0|0|1|1|0|0|0|B|0^^$0|@$1|2|3|4|5|6|7|1F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|1G|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|1H|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|1I|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|1J|8|@]|9|@$M|1K|N|1L|1|1M]]|A|$]]|$1|O|3|P|5|F|7|1N|8|@]|9|@]|A|$G|H]]|$1|Q|3|R|5|6|7|1O|8|@]|9|@]|A|$]]|$1|S|3|T|5|U|7|1P|8|@]|9|@$M|1Q|N|1R|1|1S]]|A|$]]|$1|V|3|W|5|6|7|1T|8|@]|9|@]|A|$]]|$1|X|3|Y|5|6|7|1U|8|@$M|1V|N|1W|Z|10]]|9|@]|A|$]]|$1|11|3|-4|5|6|7|1X|8|@]|9|@]|A|$]]]|12|$13|$5|14|15|16|A|$17|18]]|19|$5|1A|15|1B|A|$1C|1D|1E|-4]]]]

I had the same issue ... solution at the end !

here the eclipse log:

<pre><code>java.lang.NullPointerException
 at com.google.appengine.eclipse.wtp.maven.GaeRuntimeManager.getGaeRuntime(GaeRuntimeManager.java:85)
 at com.google.appengine.eclipse.wtp.maven.GaeRuntimeManager.ensureGaeRuntimeWithSdk(GaeRuntimeManager.java:55)
 at com.google.appengine.eclipse.wtp.maven.GaeFacetManager.addGaeFacet(GaeFacetManager.java:59)
 at com.google.appengine.eclipse.wtp.maven.GaeProjectConfigurator.configure(GaeProjectConfigurator.java:46)
</code></pre>

... it comes from "appengine maven wtp plugin" that try to get the type of GAE runtime, but seems to be null here (... getRuntimeType() --> NPE):

see class <a href="https://github.com/gwt-plugins/gwt-eclipse-plugin/blob/master/plugins/com.google.appengine.eclipse.wtp.maven/src/com/google/appengine/eclipse/wtp/maven/GaeRuntimeManager.java" rel="nofollow noreferrer">com.google.appengine.eclipse.wtp.maven/GaeRuntimeManager.java</a>

<pre><code> private static IRuntime getGaeRuntime(String sdkVersion) {
 IRuntime[] runtimes = ServerCore.getRuntimes();
 for (IRuntime runtime : runtimes) {
 if (runtime != null &amp;&amp; **runtime.getRuntimeType()**.equals(GAE_RUNTIME_TYPE)) {
</code></pre>

So, if you check in eclipse, Google App Engine is visible , but when you select it you'll see that no SDK is associated ...
<a href="https://i.stack.imgur.com/cW634.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/cW634.png" alt="preference/Server/Runtime environments"></a>

SOLUTION:
in red on the screenshot ;-)

blocks|key|172975|text|我遇到了同样的症状，上面的解决方案都没有帮助。通过再次将ear项目导入eclipse，我最终获得了问题的堆栈跟踪，并能够将其追溯到org.eclipse.m2e.wtp.MavenDeploymentDescriptorManagement，它试图删除windows临时目录中名为".mavenDeploymentDescriptorManagement“的目录，这会导致java.io.File.exists()方法产生不合理的NullPointerException，特别是因为代码已经在前面的方法中用相同的变量成功地完成了相同的事情，然后调用file.isFile()而没有问题。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|172976|在文件系统上检查这一点时发现，只能使用管理员权限访问该文件。显然，我在某个时候错误地从管理员控制台启动了eclipse。最后，我只是在windows资源管理器中显示隐藏文件，并手动删除临时文件，从而解决了问题。|172977|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

I encountered this same symptom and none of the solutions above were helpful. I finally got a stack trace of the problem by importing the ear project again to eclipse, and was able to trace this down to the org.eclipse.m2e.wtp.MavenDeploymentDescriptorManagement which was trying to delete a directory in windows' temp directory called ".mavenDeploymentDescriptorManagement", which caused an irrational NullPointerException from the java.io.File.exists() method, particularly because the code already had successfully done the same thing in a previous method with the same variable, then called file.isFile() without problem. 

Checking this out on the file system revealed that the file could only be accessed with administrator privileges. Apparently I had at some point launched eclipse from an administrator console by mistake.
In the end I just made hidden files visible in windows explorer and deleted the temporary file manually, which solved the problem.

blocks|key|2988243|text|这只是问题的另一个可能来源！|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2988244|我发现在我的例子中是由下面的resource代码块引起的：|offset|length|style|CODE|2988245|<project>
++++<build>
++++++++<resources>
++++++++++++<resource>
++++++++++++++++<directory>${basedir}/../some-folder</directory>
++++++++++++++++<targetPath>outputFolder</targetPath>
++++++++++++</resource>
++++++++<resources>
++++</build>
</project>|code-block|syntax|javascript|2988246|它包括项目文件夹中的一个文件夹(+eclipse项目是版本化项目文件夹的一个子文件夹)。|2988247|在我的例子中，我可以通过删除块并将其替换为对Build+helper+Maven插件的调用来删除错误：|2988248|<build>
++++<plugins>
++++++++<plugin>
++++++++++++<groupId>org.codehaus.mojo</groupId>
++++++++++++<artifactId>build-helper-maven-plugin</artifactId>
++++++++++++<version>1.9.1</version>
++++++++++++<executions>
++++++++++++++++<execution>
++++++++++++++++++++<id>my-own-very-cool-id-for-this-step</id>
++++++++++++++++++++<phase>generate-resources</phase>
++++++++++++++++++++<goals>
++++++++++++++++++++++++<goal>add-resource</goal>
++++++++++++++++++++</goals>
++++++++++++++++++++<configuration>
++++++++++++++++++++++++<resources>
++++++++++++++++++++++++++++<resource>
++++++++++++++++++++++++++++++++<directory>${basedir}/../some-folder</directory>
++++++++++++++++++++++++++++++++<targetPath>outputFolder</targetPath>
++++++++++++++++++++++++++++</resource>
++++++++++++++++++++++++</resources>
++++++++++++++++++++</configuration>
++++++++++++++++</execution>
++++++++++++</executions>
++++++++</plugin>
++++</plugins>
</build>|2988249|entityMap|0|LINK|mutability|MUTABLE|url|http://www.mojohaus.org/build-helper-maven-plugin/usage.html^0|0|E|8|0|0|0|M|C|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|11|8|@$D|12|E|13|F|G]]|9|@]|A|$]]|$1|H|3|I|5|J|7|14|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|15|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|16|8|@]|9|@$D|17|E|18|1|19]]|A|$]]|$1|Q|3|R|5|J|7|1A|8|@]|9|@]|A|$K|L]]|$1|S|3|-4|5|6|7|1B|8|@]|9|@]|A|$]]]|T|$U|$5|V|W|X|A|$Y|Z]]]]

Just another possible source of the problem! 

I found out that in my case it was the following <code>resource</code> block that caused it:

<pre><code>&lt;project&gt;
 &lt;build&gt;
 &lt;resources&gt;
 &lt;resource&gt;
 &lt;directory&gt;${basedir}/../some-folder&lt;/directory&gt;
 &lt;targetPath&gt;outputFolder&lt;/targetPath&gt;
 &lt;/resource&gt;
 &lt;resources&gt;
 &lt;/build&gt;
&lt;/project&gt;
</code></pre>

It included a folder from the project folder (the eclipse project is a subfolder of the versioned project folder). 

In my case, I could remove the error by removing the block and replacing it with a call to the <a href="http://www.mojohaus.org/build-helper-maven-plugin/usage.html" rel="nofollow">Build helper</a> Maven plugin:

<pre><code>&lt;build&gt;
 &lt;plugins&gt;
 &lt;plugin&gt;
 &lt;groupId&gt;org.codehaus.mojo&lt;/groupId&gt;
 &lt;artifactId&gt;build-helper-maven-plugin&lt;/artifactId&gt;
 &lt;version&gt;1.9.1&lt;/version&gt;
 &lt;executions&gt;
 &lt;execution&gt;
 &lt;id&gt;my-own-very-cool-id-for-this-step&lt;/id&gt;
 &lt;phase&gt;generate-resources&lt;/phase&gt;
 &lt;goals&gt;
 &lt;goal&gt;add-resource&lt;/goal&gt;
 &lt;/goals&gt;
 &lt;configuration&gt;
 &lt;resources&gt;
 &lt;resource&gt;
 &lt;directory&gt;${basedir}/../some-folder&lt;/directory&gt;
 &lt;targetPath&gt;outputFolder&lt;/targetPath&gt;
 &lt;/resource&gt;
 &lt;/resources&gt;
 &lt;/configuration&gt;
 &lt;/execution&gt;
 &lt;/executions&gt;
 &lt;/plugin&gt;
 &lt;/plugins&gt;
&lt;/build&gt;
</code></pre>

blocks|key|2988279|text|我不得不重新安装eclipse，删除.m2文件夹并重建jars。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2988280|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

I had to reinstall eclipse, delete .m2 folder and rebuild the jars.

blocks|key|2775630|text|删除本地maven存储库对我有帮助。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2775631|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

deleting the local maven repository helped me

blocks|key|170929|text|在我的例子中，问题是派生依赖项被其他依赖项使用的冲突，并且其中一些派生依赖项版本不可用，可能是因为我忘记部署的一些部署，因为在工作空间解析时，一切都可以工作，但当迁移到其他环境时，所有这些都会突然崩溃。此外，我还在使用版本范围|type|unstyled|depth|inlineStyleRanges|entityRanges|data|170930|maven给了我这个错误：|170931|170932|无法解析项目for+Dependency-C:1.0.0，的依赖项:MyProject:jar:1.0.0:无法解决依赖项之间的版本冲突-A:1.0.1+->+Dependency-B:1.1.0+->+->+Dependency-X:1.0.1+->+Dependency-Y:1.1.0+->jarDependency-C:1.0.0+-I:1.0.1+->依赖-J:1.1.0+->+Dependency|blockquote|offset|length|style|BOLD|170933|170934|170935|我试过了，都没用，所以...|170936|170937|+THE+SOLUTION：在所有依赖项中使用最新版本，因此maven不需要解析范围中的所有依赖项，必须小心使用，因为如果您错过了部署其中一个依赖项，构建将失败。|170938|170939|170940|只有当您使用自己的依赖项时，我才建议您使用LATEST，否则在某些第三方的未来版本中，您可能会发现一些编译或运行时错误|170941|entityMap^0|0|0|0|A|I|47|I|0|0|0|0|0|1|C|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Z|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|10|8|@]|9|@]|A|$]]|$1|E|3|F|5|G|7|11|8|@$H|12|I|13|J|K]|$H|14|I|15|J|K]]|9|@]|A|$]]|$1|L|3|-4|5|6|7|16|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|17|8|@]|9|@]|A|$]]|$1|N|3|O|5|6|7|18|8|@]|9|@]|A|$]]|$1|P|3|-4|5|6|7|19|8|@]|9|@]|A|$]]|$1|Q|3|R|5|G|7|1A|8|@$H|1B|I|1C|J|K]]|9|@]|A|$]]|$1|S|3|-4|5|6|7|1D|8|@]|9|@]|A|$]]|$1|T|3|-4|5|6|7|1E|8|@]|9|@]|A|$]]|$1|U|3|V|5|6|7|1F|8|@]|9|@]|A|$]]|$1|W|3|-4|5|6|7|1G|8|@]|9|@]|A|$]]]|X|$]]

In my case, the problem was a conflict of derived dependencies that were been used by other dependencies, and some of those derived dependencies versions were not available, maybe because some deploy that i forgot to do because with workspace resolution everything worked, but when moving to other environment all broke suddenly.
And also I was working with version ranges

maven was giving me this error:

<blockquote>
 Could not resolve dependencies for project
 MyProject:MyProject:jar:1.0.0: Could not resolve version conflict
 among Dependency-A:1.0.1 -> Dependency-B:1.1.0 ->
 Dependency-C:1.0.0, Dependency-X:1.0.1 -> Dependency-Y:1.1.0 -> Dependency-C:1.0.0, Dependency-I:1.0.1 -> Dependency-J:1.1.0 -> Dependency-C:1.0.0
</blockquote>

I tried all above and nothing worked, so...

<blockquote>
 THE SOLUTION: Use LATEST as version in all dependencies, so maven don't need to resolve all dependencies in ranges, wich must be used
 with care because if you miss to deploy one of the dependencies the
 build will fail
</blockquote>

Only I suggest you to use LATEST if you are working with your own dependencies, otherwise in some third party future version, you could find some compilation or runtime errors

blocks|key|170943|text|上面的解决方案对我不起作用，因为开放JDK13版本https://github.com/spotify/dockerfile-maven/issues/163的问题，所以我降级到开放JDK8，它对我有效|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|170944|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/spotify/dockerfile-maven/issues/163^0|P|1I|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

Above solutions did not work for me as the issue with open JDK 13 version
<a href="https://github.com/spotify/dockerfile-maven/issues/163" rel="nofollow noreferrer">https://github.com/spotify/dockerfile-maven/issues/163</a>
So I degraded to open JDK8 and it works for me

blocks|key|2988414|text|避免删除.metadata文件夹，因为它会清除所有设置，请运行配置。相反，重命名.metadata文件夹-->重新启动eclipse+-->导入项目|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2988415|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Avoid deleting the .metadata folder as it cleans up all settings, run configurations.
Instead, rename the .metadata folder --&gt; Restart eclipse --&gt; Import project

I'm developing a Java EE web project. When I try to add a dependency, this error message appears. I use Eclipse Kepler.

<blockquote>
 An internal error occurred during: "Updating Maven Project". java.lang.NullPointerException
</blockquote>

Could you help me?
Thank you.

<img src="https://i.stack.imgur.com/uGiOI.jpg" alt="enter image description here">

An internal error occurred during: "Updating Maven Project". java.lang.NullPointerException

文件系统

Eclipse

Java

我正在开发一个Java EE web项目。当我尝试添加依赖项时，出现以下错误消息。我使用的是Eclipse Kepler。在“更新Maven项目”期间发生内部错误。java.lang.NullPointerException你能帮我一下吗？谢谢。​​

问在“更新Maven项目”期间发生内部错误。java.lang.NullPointerException
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