单项选择题 GiventhatfileisareferencetoaFileobjectthatrepresentsadirectory，whichcodefragmentswillsucceedinobtainingalistoftheentriesinthedirectory？（）

填空题 Given the following code, write a line of code that, when inserted at the indicated location, will make the overriding method in Extension invoke the overridden method in class Base on the current object.   class Base {   public void print() {   System.out.println("base");   }   }   class Extention extends Base {   public void print() {   System.out.println("extension");   // insert line of implementation here   }   }   public class Q294d {   public static void main(String args[]) {   Extention ext = new Extention();   ext.print();   }   }   Fill in a single line of implementation.（）

单项选择题 Whichstatementsaretrue，giventhecodenewFileOutputStream（"data"，true）forcreatinganobjectofclassFileOutputStream？（）