I have three classes (Carnivore, Herbivore, and Plant) that extend another class (Organism). How can I tell which subclass an
Java has an instanceof operator. However, that type of thing can be contrary to object-oriented design.
You can say if( animal instanceof Carnivore ) to find out if it is a Carnivore or a descendant thereof, and you can use if( animal.getClass() == Carnivore.class ) to find out if it is exactly a Carnivore and not a descendant thereof.
However, the fact that you need to perform a check of this kind usually means that you have a flaw in your design, a missing overridable method, or something like that.
Take a look at instanceof operator
http://docs.oracle.com/javase/tutorial/java/nutsandbolts/op2.html
Note that although many people thinks that using it may be considered dangerous, they even compare to GOTO, but it's not bad in some cases. You can use it, but not really often.
objInstance instanceof Carnivore. Here objInstance is the object you want to test.
You can use the instanceof operator
You can use the instanceof keyword.
Note, however, that needing to use this is often a sign of a bad design. You should typically write method overrides in each of your derived classes so that you don't explicitly need to check which class something is.