Technology Questions

Q:

What is a Web Worker?

Answer

- A web worker is a JavaScript which runs in the background. It exists in external files. 


 - It is independent of other scripts and does not affect the performance of the page. 


 - Web workers are usually used for CPU intensive tasks.

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Subject: Web Technology

0 1861
Q:

What are Cursors? Explain Types of cursors in PL/SQL

Answer

Cursors help you manipulate the information retrieved by select statements. This can be done by assigning a name to the cursor.


Example:


CURSOR emp_cur 


IS 


SELECT emp_number from employee_tbl where employee_name = name_in;


Types of Cursors:


Implicit cursors- These cursors are not declared by the programmer. They are issued when the SQL statement is executed. The open, close and fetching is done by itself.


Example:


UPDATE employee SET salary = salary * 2.1;


Here, an implicit cursor is issued to identify the set of rows in the table which would be affected by the update.


 


Explicit cursors- These cursors are defined by programmer. They are used in queries that return multiple rows.


Example:


CURSOR emp_cur 


IS 


SELECT emp_number from employee_tbl where employee_name = name_in;

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Subject: Oracle

1 1859
Q:

What is the difference between creating a thread by extending Thread class and by implementing Runnable interface? Which one should prefer?

Answer

When creating a thread by extending the Thread class, it is not mandatory to override the run method (If we are not overriding the run method , it is useless), because Thread class have already given a default implementation for run method. But if we are implementing Runnable , it is mandatory to override the run method. The preferred way to create a thread is by implementing Runnable interface, because it give loose coupling.

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Subject: Java

0 1858
Q:

How would you automatically transfer your visitors to a new web page?

Answer

- You can do it with the help of meta tag mentioned below: 


<META HTTP-EQUIV="Refresh" CONTENT="2"; URL="https://www.yoursite.com"> 


- Place this tag between <HEAD></HEAD> . 


- It will load yousite.com in 2 seconds.

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Q:

How does a try statement determine which catch clause should be used to handle an exception?

Answer

When an exception is thrown , the catch block of the try statement are examined in the order in which they appear. The first catch block that is capable of handling the exception is executed. The remaining catch blocks are ignored

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Subject: Java

0 1855
Q:

What is the purpose of pseudo-elements?

Answer

Pseudo elements allow the use of the part of element and not the element itself. They are applied to block level element, which is used for the complete block for which the CSS is being written. This allow the subpart of an element to be styled like paragraphs and headings. For example:


selector:pseudo-element {property:value;}


p: first-line {text-transform: lowercase;}


It adds the style to the first line of the code in the paragraph.

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Subject: Web Technology

0 1854
Q:

What are the principles in providing the security for the computer programs?

Answer

- The principle of least privilege is used to provide more security to the computer programs. 


- The principle allows the designing of the program such that any unauthorized access is not allowed and only the person who owns the program will be able to access it. 


- The services provided should be able to access only those products that need the services. 


- Web servers that are involved in responding the queries of the web users provide only accessing to the HTML files that will serve the purpose of the programs. 


- Computer programs should be made such that it provides secure features of logging into the program with proper authentication.

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Subject: Web Technology

0 1854
Q:

What is the security mechanism used in java?

Answer

Java uses sand box security model.

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Subject: Java

0 1853