Please read the Tomcat manual first before you try to ask. In fact, it is stated clearly in the manual where you should put all your "beans," either in .class format or in .jar/.war form.
P.S.,
It is a good habbit to always refer to the product manuals if you have doubt. You need not to read through the whole manual, just search for the few key sections such as "installation instructions," "configurations," "trouble-shooting guide," etc. Those can most probably bring out of most common troubles easily.
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