Official definition of Maven states “Apache Maven is a software project management and comprehension tool.” For me, Maven is a build tool, that helps me manage dependencies as well. The advantage I get over Ant tool, is that it not only manages dependencies, but also downloads them automatically. Also I need not worry about transitive depeendies, that is if a jar I need for my project is inturn dependent on other jars, maven will take care of it for me.
Getting started: Using maven with Eclipse is simple. Eclipse comes with embedded maven so you need not worry about downloading or installing.
In New->Project, you can select Maven Project. It will ask you to select Archtype. An Archtype is predefine project templates. For example you can use Spring project, you can choose spring archtype. This will help you getting started by providing a sample template project, on which you can build further.
Once you create a project, you will find a pom.xml. POM stands for Project Object Model. It is fundamental Unit of Work in Maven.
A simple POM file might look like
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
Note the dependencies part. This is telling the maven which version of the required dependency is needed by application.