Component and class diagram

[Pradeep bhatt]

What is the difference between a component and class diagram?
Some time a single class becomes a component

[Ishita Gupta]

Hi,

Some time a single class becomes a component
Although a single class may become a component at times, but not the whole logic falls into the same class. It definitely makes use of some other classes say helper classes where the logic is distributed with.
So a component is rather a kind of module that may constitute of a number of classes.
does that suffice ???
Ishita
-SCJP2

[Pradeep bhatt]

When there are no helper classes?

[Idly Vada]

Class diagram and component diagram are different. Unless the application is too trivial, we'll not have a class acting as a component.Even in this case, better practice is to put this class along with support classed in a package and add it to the component diagram.
A component can be an application,applet,exe,DLL,package,database ..etc.
In java context, a component can be an application,applet,package,database,main program, sub program ..etc.
It is not a good practice to put classes in component diagram.