Example of setup that registers/unregisters non-singleton POJOs with an Event Bus.

MyApplication.java

package com.example;

import android.annotation.TargetApi;
import android.app.Application;
import android.app.ActivityLifecycleCallbacks;
import com.squareup.otto.Bus;
import javax.inject.Inject;
import javax.inject.Provider;
import dagger.ObjectGraph;
import java.util.Map;
import java.util.HashMap;

public class MyApplication extends Application {
  @Inject /* package */Provider<HomeController> home_controller;
  @Inject /* package */Provider<SettingsController> settings_controller;
  
  public void onCreate() {
    super.onCreate();
    
    registerActivityLifecycleCallbacks(activityLifecycleCallbacks());
    controller_bus = new Bus("ControllerBus");
    _presentation_controllers = bindPresentationsToControllers();
    /* Dependency injection object graph */
    final ObjectGraph object_graph = createObjectGraph();
    object_graph.inject(this);
    
    _presentation_controllers = new HashMap<Class<?>, Provider>(2);
    _presentation_controllers.put(HomeActivity.class, home_controller);
    _presentation_controllers.put(SettingsActivity.class, settings_controller);
    
    _controllers = new HashMap<Class<?>, Object>();
  }
  
  public void sendMessage(Object message) {
    controller_bus.post(message);
  }
  
  /**
   * <p>Retrieves the {@link ActivityLifecycleCallbacks} that binds Prestige to the Activity
   * lifecycles so that it can conjure Controllers behind the curtains.</p>
   */
  @TargetApi(ICE_CREAM_SANDWICH)
  public static ActivityLifecycleCallbacks activityLifecycleCallbacks() {
    return new ActivityLifecycleCallbacks() {

      /**
       * Destroys the Controller associated with the given Activity.
       */
      @Override public void onActivityDestroyed(Activity activity) {
        final Class<?> activity_class = activity.getClass();
        if (!_presentation_controllers.containsKey(activity_class)) return;

        _controllers.remove(activity_class);
      }

      /**
       * Creates the Controller associated with the given Activity.
       */
      @Override public void onActivityCreated(Activity activity, Bundle __) {
        final Class<?> activity_class = activity.getClass();
        if (!_presentation_controllers.containsKey(activity_class)) return;

        final Object controller = _presentation_controllers.get(activity_class).get();
        _controllers.put(activity_class, controller);
      }

      /**
       * Registers the Controller that is associated with the given Activity to the Controller Bus.
       */
      @Override public void onActivityResumed(Activity activity) {
        final Class<?> activity_class = activity.getClass();
        if (!_controllers.containsKey(activity_class)) return;

        controller_bus.register(_controllers.get(activity_class));
      }

      /**
       * Unregisters the Controller that is associated with the given Activity from the Controller Bus. 
       */
      @Override public void onActivityPaused(Activity activity) {
        final Class<?> activity_class = activity.getClass();
        if (!_controllers.containsKey(activity_class)) return;

        controller_bus.unregister(_controllers.get(activity_class));
      }

      @Override public void onActivityStopped(Activity activity) { }

      @Override public void onActivityStarted(Activity _) { }

      @Override public void onActivitySaveInstanceState(Activity _, Bundle __) { }
    };
  }
  
  /** Bus over which Presentations communicate to their Controllers */
  private Bus controller_bus;
  /** Provides the Controller implementation for the given Presentation Implementation */
  private Map<Class<?>, Provider> _presentation_controllers;
  /** Maintains the Controller references as they are being used */
  private Map<Class<?>, Object> _controllers;
}