I use Sony Xperia Z phone Recently i noticed that in my phone some empty folders of applications like hike and hookup are created. I did not download these applications...so how these folders came in my memory card. I had recently mounted my memory card in my friends phone which had these apps.. is it possible that these folders got copied from his phone to my memory card ? please help.
Yes exactly. Applications create (not copy) required folders as soon as a memory card is mounted. There is nothing to worry about and you can delete them manually. As an extra note - these folders are created for saving media files received and backup files.