关于scala和java 在maven项目中混编的问题

<properties>
        <scala.version>2.10.1</scala.version>
        <slf4j.version>1.7.7</slf4j.version>
        <scala.maven.version>2.10.1</scala.maven.version>
    </properties>

    <repositories>
        <repository>
            <id>scalaz</id>
            <name>scalaz</name>
            <url>http://dl.bintray.com/scalaz/releases</url>
        </repository>
        <repository>
            <id>mvnrepository</id>
            <name>Derbysoft Release Repository</name>
            <url>http://search.maven.org/remotecontent?filepath=</url>
        </repository>


        <repository>
            <id>jahia</id>
            <name>mvnrepository</name>
            <url>http://maven.jahia.org/maven2</url>
        </repository>

    </repositories>

    <dependencies>
        <dependency>
            <groupId>org.scala-lang</groupId>
            <artifactId>scala-library</artifactId>
            <version>${scala.version}</version>
            <scope>compile</scope>
        </dependency>
        <dependency>
            <groupId>org.scala-lang</groupId>
            <artifactId>scala-compiler</artifactId>
            <version>${scala.version}</version>
            <scope>compile</scope>
        </dependency>

        <dependency>
            <groupId>org.specs2</groupId>
            <artifactId>specs2_2.11</artifactId>
            <version>2.4.6</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>net.alchim31.maven</groupId>
                <artifactId>scala-maven-plugin</artifactId>
                <version>3.2.0</version>
                <executions>
                    <execution>
                        <id>compile-scala</id>
                        <phase>compile</phase>
                        <goals>
                            <goal>add-source</goal>
                            <goal>compile</goal>
                        </goals>
                    </execution>
                    <execution>
                        <id>test-compile-scala</id>
                        <phase>test-compile</phase>
                        <goals>
                            <goal>add-source</goal>
                            <goal>testCompile</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>
                    <scalaVersion>${scala.version}</scalaVersion>
                </configuration>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source>1.7</source>
                    <target>1.7</target>
                    <excludes>
                        <exclude>**/*.java</exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>