Well Dolly we aren't instantiating Reader Interface here..we are just assiging the reference of the BufferedReader object to Reader refernce varialble and since BufferedReader implements Reader hence BufferedReader "IS A" Reader..
the code is absolutely fine..sheena I hope you are using javac 1.5 compiler..because that is the only reason I can think of for not compliling the code !!!
"History would be kind to me, for I intend to write it."