If you want to get this library into your library and use it, follow these steps:
You can create a new folder within Eclipse by right-clicking on your project, and selecting New Folder. The library folder is traditionally called lib.
Drag and drop your jar folder into the new lib folder, and when prompted select Copy Files.
Selecting the Project tab at the top of the screen, and click Properties.
Select Java Build Path followed by the Libraries tab.
Click the Add JARs… button and select your JAR file from within the lib folder.
Your JAR file will now appear in both the lib and Referenced Libraries folders. You can explore the JAR's resources by clicking Referenced Libraries.