Including .jar files in Github for consistency
git, github, gradle, java, maven
Solution
Basically it is as Chris said.
You should use a build system that has a package manager. This way you specify which dependencies you need and it downloads them automatically. Personally I have worked with maven and ant. So, here is my experience:
Apache Maven:
First word about maven, it is not a package manager. It is a build system. It just includes a package manager, because for java folks downloading the dependencies is part of the build process.
Maven comes with a nice set of defaults. This means you just use the archtype plugin to create a project ("mvn archetype:create" on the cli). Think of an archetype as a template for your project. You can choose what ever archetype suits your needs best. In case you use some framework, there is probably an archetype for it. Otherwise the simple-project archetype will be your choice. Afterwards your code goes to src/main/java, your test cases go to src/test/java and "mvn install" will build everything. Dependencies can be added to the pom in maven's dependency format. http://search.maven.org/ is the place to look for dependencies. If you find it there, you can simply copy the xml snippet to your pom.xml (which has been created by maven's archetype system for you).
In my experience, maven is the fastest way to get a project with dependencies and test execution set up. Also I never experienced that a maven build which worked on my machine failed somewhere else (except for computers which had year-old java versions). The charm is that maven's default lifecycle (or build cycle) covers all your needs. Also there are a lot of plugins for almost everything. However, you have a big problem if you want to do something that is not covered by maven's lifecycle. However, I only ever encountered that in mixed-language projects. As soon as you need anything but java, you're screwed.
Apache Ivy:
I've only ever used it together with Apache Ant. However, Ivy is a package manager, ant provides a build system. Ivy is integrated into ant as a plugin. While maven usually works out of the box, Ant requires you to write your build file manually. This allows for greater flexibility than maven, but comes with the prize of yet another file to write and maintain. Basically Ant files are as complicated as any source code, which means you should comment and document them. Otherwise you will not be able to maintain your build process later on.
Ivy itself is as easy as maven's dependency system. You have an xml file which defines your dependencies. As for maven, you can find the appropriate xml snippets on maven central http://search.maven.org/.
As a summary, I recommend Maven in case you have a simple Java Project. Ant is for cases where you need to do something special in your build.
Problem
I am new to using github and have been trying to figure out this question by looking at other people's repositories, but I cannot figure it out. When people fork/clone repositories in github to their local computers to develop on the project, is it expected that the cloned project is complete (ie. it has all of the files that it needs to run properly). For example, if I were to use a third-party library in the form of a .jar file, should I include that .jar file in the repository so that my code is ready to run when someone clones it, or is it better to just make a note that you are using such-and-such third-party libraries and the user will need to download those libraries elsewhere before they begin work. I am just trying to figure at the best practices for my code commits. Thanks!