Maven JarClassLoader：警告：X.jar中的Foo.class被Y.jar隐藏（具有不同的字节码）

Question

一旦将java.mail支持添加到我的项目中：

     <dependency>
        <groupId>javax.mail</groupId>
        <artifactId>mail</artifactId>
        <version>1.4.1</version>
    </dependency>
    <dependency>
        <groupId>javax.activation</groupId>
        <artifactId>activation</artifactId>
        <version>1.1.1</version>
    </dependency>

我开始收到大量这样的警告消息（运行构建的jar时）：

JarClassLoader: Warning: javax/mail/Address.class in lib/mail-1.4.1.jar is hidden by lib/geronimo-javamail_1.4_spec-1.7.1.jar (with different bytecode)
JarClassLoader: Warning: javax/mail/AuthenticationFailedException.class in lib/mail-1.4.1.jar is hidden by lib/geronimo-javamail_1.4_spec-1.7.1.jar (with differ
ent bytecode)
JarClassLoader: Warning: javax/mail/Authenticator.class in lib/mail-1.4.1.jar is hidden by lib/geronimo-javamail_1.4_spec-1.7.1.jar (with different bytecode)
JarClassLoader: Warning: javax/mail/BodyPart.class in lib/mail-1.4.1.jar is hidden by lib/geronimo-javamail_1.4_spec-1.7.1.jar (with different bytecode)
JarClassLoader: Warning: javax/mail/EventQueue.class in lib/mail-1.4.1.jar is hidden by lib/geronimo-javamail_1.4_spec-1.7.1.jar (with different bytecode)
JarClassLoader: Warning: javax/mail/FetchProfile$Item.class in lib/mail-1.4.1.jar is hidden by lib/geronimo-javamail_1.4_spec-1.7.1.jar (with different bytecode
)

我的程序运行正常（并可以正常发送电子邮件），但是我不希望所有这数百种JarClassLoader警告...

知道如何恢复控制台日志的宁静与安静吗？

---

更新：感谢下面的Jigar Joshi的技巧，我发现不需要的geronimo-javamail_1.4_spec-1.7.1.jar来自org.apache.cxf：cxf-api：jar：2.7.1：compile ，所以我添加了排除：

   <dependency> 
        <groupId>org.apache.cxf</groupId>
        <artifactId>cxf-api</artifactId>
        <version>2.7.1</version>
        <exclusions>
          <exclusion>  
           <groupId>org.apache.geronimo.specs</groupId>
           <artifactId>geronimo-javamail_1.4_spec</artifactId>
         </exclusion>
       </exclusions> 
    </dependency>

而且mvn dependency:tree命令不再将“ geronimo”显示为依赖项，但是当我运行新生成的jar（从clean构建）时，我仍然收到所有这些警告。

还有其他建议吗？

---

更新2：这是我pom.xml中的依赖项部分：

<dependencies>
  <dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>3.8.1</version>
    <scope>test</scope>
  </dependency>


  <dependency>
    <groupId>org.apache.cxf</groupId>
    <artifactId>cxf-rt-frontend-jaxws</artifactId>
    <version>2.7.1</version>
    <type>jar</type>
    <scope>runtime</scope>
  </dependency>
  <dependency>
    <groupId>org.apache.cxf</groupId>
    <artifactId>cxf-rt-transports-http</artifactId>
    <version>2.7.1</version>
    <type>jar</type>
    <scope>runtime</scope>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-web</artifactId>
    <version>3.0.7.RELEASE</version>
  </dependency>


  <dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.26</version>
  </dependency>
  <dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-core</artifactId>
    <version>4.2.6.Final</version>
  </dependency>
  <dependency> 
    <groupId>org.apache.cxf</groupId>
    <artifactId>cxf-api</artifactId>
    <version>2.7.1</version>
    <exclusions>
      <exclusion>
    <groupId>org.apache.geronimo.specs</groupId>
    <artifactId>geronimo-javamail_1.4_spec</artifactId>
      </exclusion>
    </exclusions> 
  </dependency>
  <dependency>
    <groupId>org.apache.cxf</groupId>
    <artifactId>cxf-rt-transports-http</artifactId>
    <version>2.7.1</version>
    <type>jar</type>
  </dependency>

  <dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>servlet-api</artifactId>
    <version>2.5</version>
  </dependency>

  <dependency> 
    <groupId>javax.mail</groupId>
    <artifactId>mail</artifactId>
    <version>1.4.1</version>
  </dependency>
  <dependency>
    <groupId>javax.activation</groupId>
    <artifactId>activation</artifactId>
    <version>1.1.1</version>
  </dependency>

</dependencies>

Answer 1

该警告说您在多个jar中存在同一个类，因此可能在运行时引起麻烦

例如：

JarClassLoader: Warning: javax/mail/EventQueue.class in lib/mail-1.4.1.jar is hidden by lib/geronimo-javamail_1.4_spec-1.7.1.jar (with different bytecode)

我假设您正在从mail-1.4.1.jar而不是从geronimo-javamail_1.4_spec-1.7.1.jar寻找geronimo-javamail_1.4_spec-1.7.1.jar 。

您将必须排除此不需要的jar，以使其无法通过使用<exclusions>或<optional>标记在类路径中使用，它可能来自其他jar的依赖项

执行mvn dependency:tree来跟踪它的来临并<exclude>

---

另请参阅

• <optional> ＆ <exclusions>