As an open source enthusiast, I've used dozens (hundreds?) of libraries that are well beyond my skill or interest as a programmer. For a lot of people, including me, the available libraries are one of the things that makes a particular programming language worth using.
An open source library represents hours and days you don't have to work on a problem that's either not central to your project or, conversely, so central that your project would be otherwise out of reach. Better still, it's code you don't have to maintain—unless it's so important to you that you decide to contribute to it.
Because open source libraries are a vital component of open source programming, most programming languages have a convenient way to ensure they're easy to include in your codebase.
There are several ways to manage libraries in Java, but the one I use is Maven.
Maven is a code management framework that helps you keep track of dependencies, build targets, reporting, and documentation, all from a central location. That central location is a Project Object Model (POM) file, which is written in XML to describe the requirements and expectations of your project.
When you decide to update a library, you can update just your pom.xml file.
Should you add a debug build to your project, add it as a target in pom.xml.
When you upgrade to a new Java Virtual Machine (JVM), do it in pom.xml.
If that sounds easy, you'll be pleased to know that it's just as