在maven android构建过程中，基类java类仍然在类路径中。

Question

我遇到了一个相当奇怪的问题，因为android java实现与sun java实现不同，而且在android项目的maven构建过程中，基类java类仍然包含在类路径中(一直到最后)。我认为解决方案是在类路径上不包含java类，但我似乎找不到这样的方法。

基本上，在java.util.concurrent中有一个名为java.util.concurrent的类(在android和java中)。java类包含两个名为newTaskFor的方法，我想在android中使用这些方法，但是android实现没有它们。没问题，我只是实现它们(通过一些更改，比如使用未来而不是RunnableFuture)。这在ant (我们正在迁移的构建工具)中工作得很好。

问题是，当maven试图编译我的类(它扩展了AbstractExecutorService)，而不是只是在没有找到的时候将我的方法添加到android实现中，它会继续沿着类路径，找到java方法，并抱怨返回类型不匹配。理想情况下，我认为java类甚至不应该在android构建过程中可用，因为它们所能做的就是让您认为您可以运行实际上无法运行的方法，但是目前您可以运行android中无法使用的各种java方法，并且它会编译得很好(在maven中)。

有没有人对此有任何建议或解决方案？有人遇到类似的事吗？

编辑:以下是pom的相关部分(省略存储库等)：

<dependencies>
    <dependency>
        <groupId>org.beanshell</groupId>
        <artifactId>bsh</artifactId>
        <version>2.0b5</version>
        <optional>true</optional>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>1.2.14</version>
        <optional>true</optional>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-api</artifactId>
        <version>1.6.4</version>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>com.google.android</groupId>
        <artifactId>android-with-java</artifactId>
        <version>2.2.1</version>
    </dependency>
    <dependency>
        <groupId>org.testng</groupId>
        <artifactId>testng</artifactId>
        <version>6.1.1</version>
    </dependency>
    <dependency>
        <groupId>org.jboss.byteman</groupId>
        <artifactId>byteman-bmunit</artifactId>
        <version>2.0.0</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>bouncycastle</groupId>
        <artifactId>bcprov-jdk15</artifactId>
        <version>140</version>
        <scope>test</scope>
    </dependency>
</dependencies>
<build>
    <sourceDirectory>src</sourceDirectory>
    <resources>
        <resource>
            <directory>conf</directory>
            <includes>
                <include>*.xml</include>
            </includes>
            <excludes>
                <exclude>*-service.xml</exclude>
            </excludes>
        </resource>
        <resource>
            <directory>${project.build.directory}/schema</directory>
        </resource>
        <resource>
           <directory>${project.basedir}</directory>
           <includes>
              <include>INSTALL.html</include>
              <include>LICENSE</include>
              <include>README</include>
           </includes>
        </resource>
        <resource>
          <directory>${project.basedir}/lib</directory>
          <includes>
             <include>licenses/thirdparty*</include>
          </includes>
        </resource>
    </resources>
    <plugins>
        <plugin>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
                <source>1.6</source>
                <target>1.6</target>
                <excludes>
                    <exclude>stuff/stuff/util/JUnitXMLReporter.java</exclude>
                </excludes>
            </configuration>
        </plugin>
       <plugin>
          <groupId>org.codehaus.mojo</groupId>
          <artifactId>build-helper-maven-plugin</artifactId>
          <version>1.7</version>
          <executions>
             <execution>
                <id>add-source</id>
                <phase>validate</phase>
                <goals>
                   <goal>add-source</goal>
                </goals>
                <configuration>
                   <sources>
                      <source>target/generated-sources</source>
                   </sources>
                </configuration>
             </execution>
             <execution>
                <id>add-test-source</id>
                <phase>validate</phase>
                <goals>
                   <goal>add-test-source</goal>
                </goals>
             </execution>
          </executions>
       </plugin>
       <plugin>
            <artifactId>maven-antrun-plugin</artifactId>
            <version>1.7</version>
            <executions>
                <execution>
                    <goals>
                        <goal>run</goal>
                    </goals>
                    <phase>process-resources</phase>
                  <configuration>
                    <tasks>
                        <echo>Precompiling magic ids and protocol ids</echo>    
                        <xslt in="conf/stuff.xml" out="target/generated-sources/stuff/stuff/ClassMagicEncoding.java"
                            style="conf/stuff.xslt">
                            <param name="type" expression="Magic"/>
                        </xslt>
                        <xslt in="conf/stuff.xml" out="target/generated-sources/stuff/stuff/ClassProtocolEncoding.java"
                            style="conf/stuff.xslt">
                            <param name="type" expression="Protocol"/>
                        </xslt>
                    </tasks>
                  </configuration>
                </execution>
                <execution>
                    <id>compile</id>
                    <phase>compile</phase>
                    <goals>
                        <goal>run</goal>
                    </goals>
                    <configuration>
                        <tasks>
                            <property name="compile_classpath" refid="maven.compile.classpath"/>
                            <property name="plugin_classpath" refid="maven.plugin.classpath"/>
                            <delete dir="${project.build.directory}/schema" failonerror="false"/>
                            <mkdir dir="${project.build.directory}/schema"/>
                            <java classname="stuff.stuff.util.XMLSchemaGenerator">
                                <classpath>
                                    <pathelement path="${compile_classpath}"/>
                                    <pathelement path="${plugin_classpath}"/>
                                </classpath>
                                <arg line="-o ${project.build.directory}/schema"/>
                            </java>
                        </tasks>
                    </configuration>
                </execution>
            </executions>

            <configuration>
                <!-- prints the classpath to ensure correct jars are available -->
                <tasks>
                            <property name="compile_classpath" refid="maven.compile.classpath"/>
                    <echo>rawr=${compile_classpath}</echo>
                    <echo>java.class.path=${java.class.path}</echo>
                    <echo>CLASSPATH=${env.CLASSPATH}</echo>
                </tasks>
            </configuration>

            <dependencies>
                <dependency>
                    <groupId>xalan</groupId>
                    <artifactId>xalan</artifactId>
                    <version>2.7.1</version>
                </dependency>
                <dependency>
                    <groupId>xalan</groupId>
                    <artifactId>serializer</artifactId>
                    <version>2.7.1</version>
                </dependency>
                <dependency>
                    <groupId>ant</groupId>
                    <artifactId>ant-antlr</artifactId>
                    <version>1.6.5</version>
                </dependency>
                <dependency>
                    <groupId>org.apache.ant</groupId>
                    <artifactId>ant-nodeps</artifactId>
                    <version>1.8.1</version>
                </dependency>
            </dependencies>
        </plugin>
        <plugin>
            <groupId>org.apache.felix</groupId>
            <artifactId>maven-bundle-plugin</artifactId>
            <extensions>true</extensions>
            <configuration>
                <instructions>
                    <Main-Class>stuff.stuff.Version</Main-Class>
                    <Implementation-Version>${project.version}</Implementation-Version>
                    <Export-Package>
                        schema;version=${project.version},
                        ${project.groupId}.*;version=${project.version}
                    </Export-Package>
                    <Bundle-RequiredExecutionEnvironment>J2SE-1.6</Bundle-RequiredExecutionEnvironment>
                </instructions>
            </configuration>
        </plugin>
        <plugin>
            <groupId>com.jayway.maven.plugins.android.generation2</groupId>
            <artifactId>android-maven-plugin</artifactId>
            <version>3.2.0</version>
            <extensions>true</extensions>
                <configuration>
                    <sdk>
                         <platform>8</platform>
                    </sdk>
                    <undeployBeforeDeploy>true</undeployBeforeDeploy>
                </configuration>
        </plugin>
    </plugins>
</build>

Edit2:这是我得到的编译错误.

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:2.3.2:compile (default-compile) on project mystuff: Compilation failure: Compilation failure:
[ERROR] /home/stuff/stuff/ExecutionService.java:[775,28] <T>newTaskFor(java.lang.Runnable,T) in stuff.ExecutionService cannot override <T>newTaskFor(java.lang.Runnable,T) in java.util.concurrent.AbstractExecutorService; attempting to use incompatible return type
[ERROR] found   : java.util.concurrent.Future<T>
[ERROR] required: java.util.concurrent.RunnableFuture<T>
[ERROR] /home/stuff/ExecutionService.java:[791,28] <T>newTaskFor(java.util.concurrent.Callable<T>) in stuff.ExecutionService cannot override <T>newTaskFor(java.util.concurrent.Callable<T>) in java.util.concurrent.AbstractExecutorService; attempting to use incompatible return type
[ERROR] found   : java.util.concurrent.Future<T>
[ERROR] required: java.util.concurrent.RunnableFuture<T>
[ERROR] -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:2.3.2:compile (default-compile) on project mystuff: Compilation failure

注意: ExecutionService是扩展AbstractExecutorService的类。但是，我希望它只扩展android版本，而不是基本的java版本。我甚至尝试将newTaskFor的存根方法插入到android版本的AbstractExecutorService中(考虑到编译器应该假设我正在覆盖这些方法，而不是基本的java方法--尽管我应该注意到代码中没有@重写)，但它仍然没有工作。

没有人要求它们，但下面是我的方法声明：

protected <T> Future<T> newTaskFor(Runnable runnable, T value) 
{
//stuff
}

protected <T> Future<T> newTaskFor(Callable<T> callable) 
{
//stuff
{

我目前的理论是，它与模板类型有关，但我不太确定如何证明或修复它。

编辑6/30:我也应该注意这不是新代码。它已经有一年多的历史了，从那时起就一直在使用ant进行完美的编译。它是许多稳定版本的一部分。我们现在正在将构建过程迁移到maven，因此我正在尝试将此包设置为正确构建。

Answer 1

问题是Maven自动将Oracle JDK放在类路径上，并且Android提供了这些实现的替代实现，它们有时是不同的。在这个阶段，我不知道是否可以告诉Maven Compiler插件从其类路径中删除JDK，只需要使用类路径上的依赖项。这样就解决了这个问题。

请在Android插件问题跟踪器中创建一个问题，并可能通过询问Maven用户或开发人员列表来进行调查。