我正在尝试使用maven enforcer插件并因多个版本而失败。请你解释xom：xom是如何在xom：xom里面的？
[WARNING]
Dependency convergence error for xom:xom:1.1 paths to dependency are:
+-com.***:***:2.0.0-SNAPSHOT
+-net.unicon.cas:cas-addons:1.12
+-edu.internet2.middleware.grouper:grouperClient:2.1.0
+-xom:xom:1.1
and
+-com.***:***:2.0.0-SNAPSHOT
+-net.unicon.cas:cas-addons:1.12
+-edu.internet2.middleware.grouper:grouperClient:2.1.0
+-xom:xom:1.1
+-xom:xom:1.0b3
更新1：
mvn --version
Apache Maven 3.2.5 (12a6b3acb947671f09b81f49094c53f426d8cea1; 2014-12-14T09:29:23-08:00)
Java version: 1.7.0_79, vendor: Oracle Corporation
Java home: /Library/Java/JavaVirtualMachines/jdk1.7.0_79.jdk/Contents/Home/jre
Default locale: en_US, platform encoding: UTF-8
OS name: "mac os x", version: "10.10.5", arch: "x86_64", family: "mac
插件信息：
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-enforcer-plugin</artifactId>
<version>1.4.1</version>
<configuration>
<rules>
<DependencyConvergence/>
</rules>
</configuration>
<executions>
<execution>
<phase>validate</phase>
<goals>
<goal>enforce</goal>
</goals>
</execution>
</executions>
</plugin>
maven enforcer插件的完整输出。正如你所看到的问题是xom：xom和jaxen：jaxen
[INFO] --- maven-enforcer-plugin:1.4.1:enforce (default) @ my_code ---
[WARNING]
Dependency convergence error for jaxen:jaxen:1.1-beta-8 paths to dependency are:
+-com.some_company_name:my_code:2.0.0-SNAPSHOT
+-com.some_company_name:cas-code:2.0.0-SNAPSHOT
+-net.unicon.cas:cas-addons:1.12
+-edu.internet2.middleware.grouper:grouperClient:2.1.0
+-xom:xom:1.1
+-jaxen:jaxen:1.1-beta-8
and
+-com.some_company_name:my_code:2.0.0-SNAPSHOT
+-com.some_company_name:cas-code:2.0.0-SNAPSHOT
+-net.unicon.cas:cas-addons:1.12
+-edu.internet2.middleware.grouper:grouperClient:2.1.0
+-xom:xom:1.1
+-jaxen:jaxen:1.1-beta-8
+-jaxen:jaxen:1.1-beta-6
and
+-com.some_company_name:my_code:2.0.0-SNAPSHOT
+-com.some_company_name:cas-code:2.0.0-SNAPSHOT
+-net.unicon.cas:cas-addons:1.12
+-edu.internet2.middleware.grouper:grouperClient:2.1.0
+-xom:xom:1.1
+-jaxen:jaxen:1.1-beta-8
+-jaxen:jaxen:1.0-FCS
[WARNING]
Dependency convergence error for xom:xom:1.1 paths to dependency are:
+-com.some_company_name:my_code:2.0.0-SNAPSHOT
+-com.some_company_name:cas-code:2.0.0-SNAPSHOT
+-net.unicon.cas:cas-addons:1.12
+-edu.internet2.middleware.grouper:grouperClient:2.1.0
+-xom:xom:1.1
and
+-com.some_company_name:my_code:2.0.0-SNAPSHOT
+-com.some_company_name:cas-code:2.0.0-SNAPSHOT
+-net.unicon.cas:cas-addons:1.12
+-edu.internet2.middleware.grouper:grouperClient:2.1.0
+-xom:xom:1.1
+-xom:xom:1.0b3
[WARNING] Rule 0: org.apache.maven.plugins.enforcer.DependencyConvergence failed with message:
Failed while enforcing releasability the error(s) are [
Dependency convergence error for jaxen:jaxen:1.1-beta-8 paths to dependency are:
+-com.some_company_name:my_code:2.0.0-SNAPSHOT
+-com.some_company_name:cas-code:2.0.0-SNAPSHOT
+-net.unicon.cas:cas-addons:1.12
+-edu.internet2.middleware.grouper:grouperClient:2.1.0
+-xom:xom:1.1
+-jaxen:jaxen:1.1-beta-8
and
+-com.some_company_name:my_code:2.0.0-SNAPSHOT
+-com.some_company_name:cas-code:2.0.0-SNAPSHOT
+-net.unicon.cas:cas-addons:1.12
+-edu.internet2.middleware.grouper:grouperClient:2.1.0
+-xom:xom:1.1
+-jaxen:jaxen:1.1-beta-8
+-jaxen:jaxen:1.1-beta-6
and
+-com.some_company_name:my_code:2.0.0-SNAPSHOT
+-com.some_company_name:cas-code:2.0.0-SNAPSHOT
+-net.unicon.cas:cas-addons:1.12
+-edu.internet2.middleware.grouper:grouperClient:2.1.0
+-xom:xom:1.1
+-jaxen:jaxen:1.1-beta-8
+-jaxen:jaxen:1.0-FCS
,
Dependency convergence error for xom:xom:1.1 paths to dependency are:
+-com.some_company_name:my_code:2.0.0-SNAPSHOT
+-com.some_company_name:cas-code:2.0.0-SNAPSHOT
+-net.unicon.cas:cas-addons:1.12
+-edu.internet2.middleware.grouper:grouperClient:2.1.0
+-xom:xom:1.1
and
+-com.some_company_name:my_code:2.0.0-SNAPSHOT
+-com.some_company_name:cas-code:2.0.0-SNAPSHOT
+-net.unicon.cas:cas-addons:1.12
+-edu.internet2.middleware.grouper:grouperClient:2.1.0
+-xom:xom:1.1
+-xom:xom:1.0b3
]
[INFO] ------------------------------------------------------------------------