How to use library jar after import to existing project

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http://stackoverflow.com – I create gallery app , then i want to add zoom effect to images in my gallery by adding an external library called : ImageVIewZoom.jar From this link: https://github.com/kilaka/ImageViewZoom I only add the jar file not all ImageViewZoom project to my project . I add the library following this way : 1- my libs -> right click -> Import -> File System -> ImageViewZoom.jar 2- myProject -> right click -> Properties -> Java Build Path -> Libraries -> Add Jar -> ImageViewZoom.jar. Now jar file already in my project how can i utilize or use jar class inside my gallery class so i finally when (HowTos)