Maven测试错误：javac：源版本1.8需要目标版本1.8

如果我运行mvn -e test，则会收到错误消息：

[INFO] Error stacktraces are turned on.
[INFO] Scanning for projects...
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building Skat09 0.0.1-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[WARNING] The artifact org.apache.commons:commons-io:jar:1.3.2 has been relocated to commons-io:commons-io:jar:1.3.2
[INFO] 
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ Skat09 ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 6 resources
[INFO] Copying 191 resources
[INFO] 
[INFO] --- maven-compiler-plugin:3.3:compile (default-compile) @ Skat09 ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 64 source files to /home/buzz-dee/Workspace/skat09/target/classes
[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR : 
[INFO] -------------------------------------------------------------
[ERROR] javac: source release 1.8 requires target release 1.8

[INFO] 1 error
[INFO] -------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.729 s
[INFO] Finished at: 2015-10-02T23:17:02+02:00
[INFO] Final Memory: 10M/298M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.3:compile (default-compile) on project Skat09: Compilation failure
[ERROR] javac: source release 1.8 requires target release 1.8
[ERROR] -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.3:compile (default-compile) on project Skat09: Compilation failure
javac: source release 1.8 requires target release 1.8


    at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:212)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:116)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:80)
    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)
    at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:307)
    at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:193)
    at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:106)
    at org.apache.maven.cli.MavenCli.execute(MavenCli.java:862)
    at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:286)
    at org.apache.maven.cli.MavenCli.main(MavenCli.java:197)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)
Caused by: org.apache.maven.plugin.compiler.CompilationFailureException: Compilation failure
javac: source release 1.8 requires target release 1.8


    at org.apache.maven.plugin.compiler.AbstractCompilerMojo.execute(AbstractCompilerMojo.java:911)
    at org.apache.maven.plugin.compiler.CompilerMojo.execute(CompilerMojo.java:129)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:134)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:208)
    ... 20 more
[ERROR] 
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException

这是我的Maven pom.xml：

<plugins>
  <plugin>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.3</version>
    <configuration>
        <rules>
            <requireJavaVersion>
                <version>1.8</version>
            </requireJavaVersion>
        </rules>
      <source>1.8</source>
      <tagret>1.8</tagret>
    </configuration>
  </plugin>
</plugins>

来自的输出mvn -version：

Apache Maven 3.3.3 (NON-CANONICAL_2015-07-27T12:38:38_root; 2015-07-27T11:38:38+02:00)
Maven home: /opt/maven
Java version: 1.8.0_60, vendor: Oracle Corporation
Java home: /usr/lib/jvm/java-8-jdk/jre
Default locale: de_DE, platform encoding: UTF-8
OS name: "linux", version: "4.2.2-1-arch", arch: "amd64", family: "unix"

Java JDK（archlinux-java get）设置：

java-8-jdk

Java编译器版本（javac -version）：

javac 1.8.0_60

我还尝试添加：

<verbose>true</verbose>
<fork>true</fork>
<executable>/usr/lib/jvm/java-8-jdk/bin/javac</executable>
<compilerVersion>1.8</compilerVersion>

到POM中的configuration元素maven-compiler-plugin。

上述错误是什么问题，我该如何解决？