gistfile1.xml

<build>
      <plugins>
...
         <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.1</version>
            <executions>
               <execution>
                  <id>default-compile</id>
                  <configuration>
                     <showDeprecation>true</showDeprecation>
                     <showWarnings>true</showWarnings>
                     <compilerArguments>
                        <source>${maven.compiler.target}</source>
                        <target>${maven.compiler.source}</target>
                     </compilerArguments>
                  </configuration>
               </execution>
               <execution>
                  <id>default-testCompile</id>
                  <configuration>
                     <showDeprecation>true</showDeprecation>
                     <showWarnings>true</showWarnings>
                     <compilerArguments>
                        <source>${maven.compiler.testTarget}</source>
                        <target>${maven.compiler.testSource}</target>
                     </compilerArguments>
                  </configuration>
               </execution>
            </executions>
         </plugin>
...
      </plugins>
   </build>