Maven compile sources version 1.5

Add following to pom.xml:

<build>
  <plugins>
      <plugin>
          <groupId>org.apache.maven.plugins</groupId>
          <artifactId>maven-compiler-plugin</artifactId>
          <configuration>
              <source>1.5</source>
              <target>1.5</target>
          </configuration>
      </plugin>
  </plugins>
</build>