BusProvider.java

// Provided by Square under the Apache License
public final enum BusProvider {
    INSTANCE;
  
    public static final Bus BUS;

	private BusProvider() {
		BUS = new Bus();
	}
}

CallBus.java

BusProvider.INSTANCE.BUS;
// or do something useful with it:
BusProvider.INSTANCE.BUS.post(someObj);