Accessing a Class which extends an AbstractClass which itself extends another Abstract Class

Question

I had a number of classes which extended an abstract class. Each of these classes could be returned in a 'set' by a method elsewhere in the project.

public abstract class AbstractBuilding{
    ....
}

public class ABuilding extends AbstractBuilding{
    ....
}     

In another class:

World world = worldManager.getWorld();   
   for (AbstractBuilding building : world.getBuildings()){
       if (building.toString().contains("SomeSequence")){
            //Do Something
       }
    }

Where world.getBuildings() returns a set of all Abstract Buildings/classes.

Due to design changes, ABuilding is now an Abstract Class itself in addition to extending the original AbstractBuilding. And more classes extend from ABuilding.
Note: I still have other regular classes which extend AbstractBuilding as before - ABuilding2

public abstract class AbstractBuilding{
    ....
}
public class ABuilding2 extends AbstractBuilding{
    ....
}

public abstract class ABuilding extends AbstractBuilding{
    ....
}

public class TheBuilding extends ABuilding{
    ....
}

When I call the world.getBuildings method now, I still get the set of all abstract buildings, which include buildings such as TheBuilding as it extends ABuilding which itself extends AbstractBuilding.

Is there some way that I can identify if a building in the returned set of buildings extends from this new abstract building?