execute maven project with command line interface

Question

I have a maven project and use exec-maven-plugin as following

<build>
    <plugins>
        <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>exec-maven-plugin</artifactId>
            <version>1.2.1</version>
            <configuration>
                <mainClass>aventurier.App</mainClass>
            </configuration>
        </plugin>
    </plugins>
</build>    

When I run my project with the following command line

mvn -e clean install exec:java -Dexec.args="carte.txt test1.txt"

It sends me an error which is probably due to the version of the compiler (it probably compile with Java 5). How to tell to compile in Java 8 and run in Java 8?