Actually this is the problem we are facing with ADT 17 you have to put your jar file into libs folder in order to overcome this exception
so right click on your project –>create a folder with name libs
and follow this step in
right click (on libs folder) -->import-->File System-->browse to select your jar file and hit finish and run you project.
after that
right click on the project --> Built Path-->java built path-->add jars select your jar file from your libs folder