Missing "\" when building dropwizard demo mvn project (page40)

```
mvn -B archetype:generate \
-DarchetypeGroupId=io.dropwizard.archetypes \
-DarchetypeArtifactId=java-simple -DarchetypeVersion=0.9.2 \
-DgroupId=com.redhat.examples.dropwizard \
-DartifactId=hola-dropwizard -Dversion=1.0 -Dname=HolaDropwizard
```