Project Object Model

===
pom.xml file is essentially the project's metadata file 
that describes the various aspects of the project.
It describes the project's name, group, version, 
dependecies, and many other things.
===
Ok, as we have create a project with maven and 
import it into eclipse, when we develop the project 
we want to use a jar file in our local repository(for example jzmq.jar), 
so we add the jar file into our local repository first, 
then edit the pom file to tell this project about this, 
then tell eclipse this change.

If you want to use zeroMQ, you should install zeroMQ in 
your system, then you should install jzmq.jar, now you 
have your jzmq.jar, you want to add it to your local repository, 
do as below:
>>mvn install:install-file -Dfile=/usr/local/share/java/zmq.jar 
-DgroupId=com.sysdev.zeromq -DartifactId=zeromq -Dversion=3.2.2 
-Dpackaging=jar

Then you will see the prompt that maven have installed 
zmq.jar to your local repository.

Then you can edit your pom.xml file to add 
this jar file to the project you are developing.
Add below to your pom.xml in 
<dependencies></dependecies>

<dependency>
  <groupId>com.sysdev.zeromq</groupId>
  <artifactId>zeromq</artifactId>
  <version>3.2.3</version>
  <scope>compile</scope>
</dependency>

ok, run
>>mvn eclipse:eclipse 
to update it to your eclipse.

OK, you can use zeromq in your project after you import it.