Java Questions

Two types of classes:

1) Top Level Class

2) Classes within Class

       i) member classes

             a) static member class

             b) non static member class

      ii) local classes

      iii) anonymous classes

Various elements of OOP are:

• Object

• Class

• Method

• Encapsulation

• Information Hiding

• Inheritance

• Polymorphism

Local class is class defined inside method

EX;

class A { // top level class

  public static void main(string[] args) {

   class B { // local class

   }

}

}

JDBC technology is an API (included in both J2SE and J2EE releases) that provides cross-DBMS connectivity to a wide range of SQL databases and access to other tabular data sources, such as spreadsheets or flat files. With a JDBC technology-enabled driver, you can connect all corporate data even in a heterogeneous environment.

boolean isFile();

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.

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