Technology Questions

The wait(), notify(), and notifyAll() methods are used to provide an efficient way for threads to wait for a shared resource. When a thread executes an object's wait() method, it enters the waiting state. It only enters the ready state after another thread invokes the object's notify() or notifyAll() methods..

Web portal is a business gateway, It organizes business operations.

Ex: Online shopping portals, Job portals etc...

A stored procedure is a segment of declarative SQL statements stored inside the database catalog. A stored procedure can be invoked by triggers, other stored procedures or applications such as Java, C#, PHP, etc.

Advantages 

- Typically stored procedures help increase the performance of the applications. Once created, stored procedures are compiled and stored in the database. However MySQL implements the stored procedures slightly different. MySQL stored procedures are compiled on demand. After compiling a stored procedure, MySQL puts it to a cache. And MySQL maintains its own stored procedure cache for every single connection. If an application uses a stored procedure multiple times in a single connection, the compiled version is used, otherwise the stored procedure works like a query.

- Stored procedures helps reduce the traffic between application and database server because instead of sending multiple lengthy SQL statements, the application has to send only name and parameters of the stored procedure.

- Stored procedures are reusable and transparent to any applications. Stored procedures expose the database interface to all applications so that developers don’t have to develop functions that are already supported in stored procedures.

- Stored procedures are secure. Database administrator can grant appropriate permissions to applications that access stored procedures in the database without giving any permission on the underlying database tables.

Disadvantages

- If you use a lot of stored procedures, the memory usage of every connection that is using those stored procedures will increase substantially. In addition, if you overuse a large number of logical operations inside store procedures, the CPU usage will also increase because database server is not well-designed for logical operations.

- A constructs of stored procedures make it more difficult to develop stored procedures that have complicated business logic.

- It is difficult to debug stored procedures. Only few database management systems allow you to debug stored procedures. Unfortunately, MySQL does not provide facilities for debugging stored procedures.

-It is not easy to develop and maintain stored procedures. Developing and maintaining stored procedures are often required specialized skill set that not all application developers possess. This may lead to problems in both application development and maintenance phases.

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.

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

- Files can be transferred to the server by using the FTP protocol also known as File Transfer Protocol. 

- FTP is used as a standard network protocol that transfers the file from one computer to another computer using the TCP protocol network.

- This uploads the pages and other documents that are stored in private disk to the public web hosting server. 

- FTP is used on a client server architecture that allows different controls and data connections between the client and the server. 

- FTP uses clear-text sign in protocol that allows the client to use the user name and password for authentication purpose.

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

new ClassName( arg1, arg2, .... argN);

Ex:

Class sample {

   Sample(int a) {

   System.out.println("arg con a =" +a);

   }

}

class Demo {

    Public static void main( String[] args) {

     Sample s1= new Sample(23);

     Sample s2= new Sample(45);

    }

}