Technology Questions

A throw is used to throw an exception manually, where as throws is used in the case of checked exceptions, to tell the compiler that we haven't  handled the exception, so that the exception will be handled by the calling function.

Transmission is a physical movement of information and concern issues like bit polarity, synchronization, clock etc.

Communication means the meaning full exchange of information between two communication media

These are accessibility modifiers. Private is the most restrictive, while public is the least restrictive. There is no real difference between protected and the default type (also known as package protected) within the context of the same package, however the protected keyword allows visibility to a derived class in a different package.

=> 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.

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) );

The JDBC Driver provides vendor-specific implementations of the abstract classes provided by the JDBC API. This driver is used to connect to the database.

Joins are used to combine data of one or more tables. Joins should be used when there is abundant data. Joins can be LEFT, RIGHT, OUTER, INNER or even SELF JOIN. The purpose is to bind data from multiple tables without any receptivity

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 "]]>":