Technology Questions

An abstract class can have instance methods that implement a default behavior. An Interface can only declare constants and instance methods, but cannot implement default behavior and all methods are implicitly abstract. An interface has all public members and no implementation. An abstract class is a class which may have the usual flavors of class members (private, protected, etc.), but has some abstract methods.

The JVM performs three main tasks:

• Loads code

• Verifies code

• Executes code

Oracle NOT NULL is used on a column to ensure that the value for that column can never be NULL.
Example:
Below, the constraint is that the id should never be NULL. If it is, oracle throws an error.
create table employee ( id number NOT NULL, Name varchar(200) );

=> When a consumer wants to buy a certain product, he go to the website and selects the product he wants to buy. 

=> Once the product is selected, the consumer transaction is moved to the online transaction server where he places an order. 

=> The informations is exchanged over a secure channel through a private gateway to a processing network. 

=> The networked banks accept or reject the transaction.

 All this happens in just a matter of seconds. E-commerce is a very secure due to the SSL (Secure Socket Layer) technology.

strat_form using this we can open many layoutses
open_form using this we can open the layout
performance will be high

A NSArray’s contents can not be modified once it’s been created whereas a NSMutableArray can be modified as needed, i.e items can be added/removed from it.

CDATA - (Unparsed) Character Data

The term CDATA is used when you dont want some text data to be parsed by the XML parser.

A CDATA section starts with "<![CDATA[" and ends with "]]>": 

-To store information usually relevant to browsers and search engines.

-To only store information usually relevant to browsers

-To only store information about search engines.

-To store information about external links