One way of viewing nouns in English is as a hierarchy. At the top of the hierarchy you have "thing", and as you descend the pyramid you get more and more specific. "What is that thing?" -> "What is that animal?" -> "What is that mammal?" -> "What is that ungulate?", etc.

There are times when it is appropriate to use "animal", and times when it is appropriate to use "ungulate". It depends on context. OO allows you to have the same levels of abstraction, and it can be a powerful tool.

NOW, having said that, there are two problems with this:

1) Not everything is a noun. Sometimes you want to deal with verbs.

2) Realistically, these hierarchies (in Java) tend to become overly-complicated over time. That's what OP is talking about.

There are cases, though, like the aforementioned Throwable, where having a deeply (more than 3 layers deep) nested hierarchy is wholly appropriate.