This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
I think u'll have to delete it thro' coding methods.U can write a method that accepts the directory path,using this delete the files of the current directory ,in case of sub-folders call this funtion recursively with the sub-folder path.This is the way I know. Happy middling with java. Netharam.