The Dependencies panel displays the libraries, their paths, and deployment strategies in the project as well as enables you to Add a Library, Remove a Library, change the order of libraries, and Change a Library Deployment Strategy used in the project.
Libraries - If you want to use the same set of sources in multiple projects, you can set it in the project as a library and share it among different users and projects as a separate project. There are two types of libraries that can be added to a project:
Libraries that depend on existing library projects.
Libraries that depend on existing JAR files.
Use a library that depends on a JAR file when the JAR file satisfies one of the following conditions:
The JAR file represents an API that resides on the target platform but is not deployed.
The JAR file contains classes that must be included in the JAR file generated for the project.