javabean vs servlet [duplicate]

Question

I was searching for difference between javabean and servlet. I found

Servlet corresponds a Controller JavaBean corresponds a Model 

and

java bean is a reusable component,where as the servlet is the java program which extends the server capability

Now, what does re-usable means in javabean. Can't we re-use servlet ?

I will appreciate, if anyone can explain this, with few examples.