Definition of and difference between modules and components

If you search for my title, you’ll find a lot of discussions about the differences of modules and components.

By reading literature about software architecture I also tried to get a definition of it. In my opinion it is really important to have a good overview what this terms mean to communicate ideas without any problems.

So let me share with you what I found out about them.

Modules

Modules are a set of parts or independent units. They can be used to create a more complex structure.

So code which is related to each other creates a module.

In the Java world you’d say that a package is a module. In a package you can find a group of classes which are bounded together to a module.

For an architect it is really important to avoid a too high coupling between modules. This shall ensure the reusability and interchangeability of modules.

Components

The physical manifestation of a module is defined as a component. So packaging a Java application into .jar file will create a component.

Thinking of the simplest component is a library: A wrapper of code.

One component can contain different modules and bundle them together to a service.

For an architect it is important to identify components in a new project.

This can happen by a discovering components process.

You could mean the same when you talk about components and modules. If you do this just ask yourself: Are you looking at it during the development or after you have bundled your code?