When I first learned Linux, I used Slackware 3.0. In those days, if you wanted to install extra software, you pretty much had to compile it yourself. And they didn’t even have configure scripts back then, if I recall correctly. Eventually, Redhat took over, and software was easier to install via RPM packages. At first, RPMs weren’t available for everything, so you still had to compile some stuff, but eventually they became pretty ubiquitous. Dependencies could be a big pain though. You download one RPM you want, and you find out you need to download five more that it depends on. And those five each depend on five others. Remember rpmfind.net? Then came yum and apt-get, and those trouble were alleviated.
Now, building Java apps is almost like managing a Linux system. There are so many great third party libraries available, you can find ones to do almost any common task you need, saving lots of time when coding stuff. But, the people that write those libraries also use other libraries. Things like Hibernate have a lot of dependencies. Getting all of the jars for the libraries you need can be somewhat like the old RPM hunt. This is where Maven comes in. Just tell it you need Hibernate and it will make sure you have everything else you need. It’s pretty awesome, and it can completely eliminate those sessions where you waste a lot of time looking for jar files.