I think it is really important that you identify the "bad smells" in a code that you have written, simply since they are not good to have.
There are number of such "bad smells" which have been recognized and expected, programmers to be aware of. You can check most of them from here.
I had a research on the internet for a Eclipse plug-in in order to identify so called "bad smells". Luckily I found this wonderful plug-in called "JDeodorant".
JDeodorant is capable of recognizing four main types of "bad smells" that can be found in your code namely God Class, Long Method, Type Checking and Feature Envy. I have created a screen cast on "how to use JDeodorant?" and here it is.
Hope this post made your attention towards possible "bad smells" in your code, and hopefully correcting them (Oh I forgot to tell, using JDeodorant you can correct most of these bad smells as well ).
Happy Coding!! :)