Java Questions

To create directory on the HD we use mkDir() method:

boolean mkDir();

This method returns true if the directory is created on HD

This method returns false if the directory is already existing on HD

A table of data representing a database result set, which is usually generated by executing a statement that queries the database.

ResultSet object maintains a cursor pointing to its current row of data. Initially the cursor is positioned before the first row. The next method moves the cursor to the next row, and because it returns false when there are no more rows in the ResultSet object, it can be used in a while loop to iterate through the result set.

abstract method is a method declared with abstract modifier but  with out body.

Local class is class defined inside method

EX;

class A { // top level class

  public static void main(string[] args) {

   class B { // local class

   }

}

}

boolean isFile();

An abstract class is an incomplete class. An abstract class is defined with the keyword abstract . We cannot create an object of the abstract class because it is not complete. It sets a behavioral protocol for all its child classes.

- The Set interface provides methods for accessing the elements of a finite mathematical set

- Sets do not allow duplicate elements

- Contains no methods other than those inherited from Collection

- It adds the restriction that duplicate elements are prohibited

- Two Set objects are equal if they contain the same elements

File[] listFiles();

this method returns list of files stored in a directory.