Managing projects - IntelliJ IDEA in Action - page 108

Work in IDEA begins with the concept of a project. A project encapsulates all your
source code, library files, and build instructions into a single organizational unit.
Since version 4.0, IDEA 's modules and libraries let you segregate larger, complex
projects in more manageable structures that can share common code. Modular-
ized projects are also a great benefit when you're building enterprise applications
composed of several different components with complex interdependencies.
Even if you've used an older version of IDEA extensively, we recommend that you
not skip this chapter due to the fundamental changes in project management.

4.1 Understanding IDEA's project strategy

When you work on source code in IDEA , you do so in the context of a project .
Because everything in IDEA revolves around the project, it's important to have a
firm understanding of how and why IDEA handles projects the way it does.

4.1.1 Examining the IDEA project hierarchy

If you've never used an integrated development environment ( IDE ) like IDEA
before, you may not immediately understand why you have to define a project
before diving into your work. Remember, however, that IDEA isn't a simple text
editor; it's a Java development environment. As such, you can't just start typing in
your source code willy-nilly. First you have to create a project.

What is a project?
A project in IDEA is an organizational unit that represents a complete software
solution. Your finished product may be decomposed into a series of discrete, iso-
lated modules, but it's a project definition that brings them together, relates them
with dependencies, and ties them into a greater whole.
Projects don't themselves contain development artifacts such as source code,
build scripts, or documentation. They're the highest level of organization in the
IDE , and they define project-wide settings as well as collections of what IDEA
refers to as modules and libraries.

What is a module?
A module in IDEA is a discrete unit of functionality that can be run, tested, and
debugged independently. Modules contain the development artifacts for their
specific task; this includes such things as source code, build scripts, unit tests,
documentation, and deployment descriptors. IDEA supports different types of
modules, from plain Java applications to web apps, EJB modules, and so on. For
many projects, a single module will suffice.