Creating an injector with Google Guice

Question

I’m trying to use Google Guice in my application. So I created a Module by binding an interface with an implementation...

public class ApplicationModule extends AbstractModule {

    @Override
    protected void configure() {
        super.configure();

        bind(UserDAO.class).in(Singleton.class);
        bind(UserDAO.class).to(UserDAOImpl.class);

    }

}

But when I’m going to instantiate the injector using

Injector injector = Guice.createInjector(new ApplicationModule());

Google Guice says that bind was not made...

com.google.inject.CreationException: Unable to create injector, see the following errors:

1) No implementation for br.com.brunots.training.simple_rest_application.dao.UserDAO was bound.
  Did you mean?
    br.com.brunots.training.simple_rest_application.dao.UserDAO bound  at br.com.brunots.training.simple_rest_application.guice.ApplicationModule.configure(ApplicationModule.java:16)

  at br.com.brunots.training.simple_rest_application.guice.ApplicationModule.configure(ApplicationModule.java:15)

2) A binding to br.com.brunots.training.simple_rest_application.dao.UserDAO was already configured at br.com.brunots.training.simple_rest_application.guice.ApplicationModule.configure(ApplicationModule.java:16).
  at br.com.brunots.training.simple_rest_application.guice.ApplicationModule.configure(ApplicationModule.java:15)

What I’m doing wrong?