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What are the types of cookies?

Cookies can be broadly classified into 2 types

1. Persistent cookies: Remain on the client computer, even after the browser is closed. You can configure how long the cookies remain using the expires property of the Http Cookie object.

2. Non-Persistent cookies: If you don't set the Expires property, then the cookie is called as a Non-Persistent cookie. Non-Persistent cookies only remain in memory until the browser is closed.

There two type of cookies ..
 Persistent cookies: cookies are stored on your computer hard disk. They stay on your hard disk and can be accessed by web servers until they are deleted or have expired. 
public void SetPersistentCookies(string name, string value){
 HttpCookie cookie = new HttpCookie(name);
 cookie.Value = value;
 cookie.Expires = Convert.ToDateTime(“12/12/2008”);

Non-persistent cookies: cookies are saved only while your web browser is running. They can be used by a web server only until you close your browser. They are not saved on your disk.
 public void SetNonPersistentCookies(string name, string value){
 HttpCookie cookie = new HttpCookie(name);
 cookie.Value = value;

What is Cache?

    Cache is the process performed by search engine crawler at a regular interval of time. It used to scan and take a snapshot of each page over world wide web as well as a store as a backup copy. Almost every search engine result page incorporates a cached link for every site. However, clicking on cached link show you the last Google cached version of that specific page rather than of current version. Also, you can directly prefix “cache:” with the desired URL to view it cached version

Page caching is another method which can help you to improve the load time of your web pages and thus optimize your site for the search engines. Page load time can significantly impact your user experience and your site’s ability into convert visitors into buyers or into leads. In fact, experiments at Google have revealed that just a half second’s difference in load times can cause up to a 20% reduction in web traffic. For this reason, the search engine companies are considering page load time to be an increasingly important factor for determining your site’s rank in the search results. This means you’ll need to take measure in reducing the size of your image files and your pages as a part of your SEO strategy.

What is a NullPointer Exception in and how to fix it

Null pointer exception means you are trying to access a member field or a function from an object which is null. for example you created a object of a class object name is "ClassAobj" and you want a variable value from class which is assign and initilize in that class now int a = ClassAobj.Number1; if "ClassAobj" is null then you can not access the value of Number1 . for fixing it ,either you have to initilize the class or you have to full if condition if(ClassAobj != null) { int a = ClassAobj.Number1; }

You are trying to use something that is null (or Nothing in VB.NET). This means you either set it to null, or you never set it to anything at all.

Like anything else, null gets passed around. If it is null in method "A", it could be that method "B" passed a null to method "A".

The rest of this article goes into more detail and shows mistakes that many programmers often make which can lead to a NullReferenceException.

What is difference between config() and run() method in AngularJS? which runs first ?

AngularJS   .Config() Method - configuration gets executed during the configuration phase. We can inject providers and constants into configuration block. This block is used to inject module wise configuration settings to prevent accidental instantiation of services before they have been fully configured.

AngularJS  .Run method – Run method is executed after the configuration method. we can inject instances and constants in run method. The run method is a great place to put event handlers that need to be executed at the root level for the application. For example, authentication handlers.

Configuration():  get executed during the provider registrations and configuration phase. Only providers and constants can be injected into configuration blocks. This is to prevent accidental instantiation of services before they have been fully configured.

Run(): get executed after the injector is created and are used to kickstart the application. Only instances and constants can be injected into run blocks. This is to prevent further system configuration during application run time.Run blocks are the closest thing in AngularJS to the main method. It is executed after all of the services have been configured and the injector has been created. Run blocks typically contain code which is hard to unit-test, and for this reason should be declared in isolated modules, so that they can be ignored in the unit-tests.

How do you create a Persistent Cookie?

You create a persistent cookie the same way as session cookies except that you set the Expires property to a Date in the future which will store the Cookie to the client computer hard drive.

//Code to create a UserName Persistent Cookie that lives for 10 days
HttpCookie CookieObject = new HttpCookie("UserName", "David");
CookieObject.Expires = DateTime.Now.AddDays(10);

//Code to read the Cookie created above

Cookies have an expiration date implicitly or explicitly set which controls how long they last (subject to the user agent actually enforcing it). A cookie may persist only for the duration of the session (or an even shorter period).

If a cookie is valid, it will be passed along with the HTTP request to the domain that it originated from. Only the domain that set the cookie can read the cookie (though there are ways to exploit this, such as cross-site scripting).

  • If you want a cookie to expire at a specific time, set an expiration date on it using the client or server-side language of your choice.

  • If you want the cookie to expire when the session ends, don't set an expiration date.

Why Constructor name is same as Class name

Constructor is called immediately after an object of a class is created. To reduce the number of keywords in Java, name of the constructor is defined same as the Class name. The Java developers don't want to include new keyword for constructor. They want to keep it simple and precise.
So that it can be unambigously identified as the constructor. and how its get invoked implicitly when we create object of that class. It is invoked by the compiler because it has already been unambiguously identified because of its naming sheme.

Its more of a convenient convention rather than a logical reason. Methods in a class which have the same name as the class name are constructors - the easiest and simplest way to identify a method as a constructor. This is much better than telling the compiler about the constructor methods using config files or using annotations over methods…

debugging error "Could not find prelaunch task 'null' "

Have you installed angularJS via npm? May be this is because of invalid JSON or task name missing in json file

The error occurs because Visual Studio Code cannot find any task in the tasks.json with the taskName value set to 'build'.

The preLaunchTask property of the launch.json file defines the task that should be executed before the script is launched. From the question, Visual Studio Code has been configured to run the task build before launching the script:

preLaunchTask: 'build'

But there's no task named 'build' in the tasks.json file.

To fix this, you should change the value of the preLaunchTask property to 'exe', which is the build task that has been defined in the tasks.json file.

Error opening a .txt file in C++

do it in following way
var fileStream = new FileStream(@"c:\file.txt", FileMode.Open, FileAccess.Read);
using (var streamReader = new StreamReader(fileStream, Encoding.UTF8))
    string line;
    while ((line = streamReader.ReadLine()) != null)
        // process the line

Why do we use jQuery?

  • Easy to use and learn.
  • Easily expandable.
  • Cross-browser support (IE 6.0+, FF 1.5+, Safari 2.0+, Opera 9.0+)
  • Easy to use for DOM manipulation and traversal.
  • Large pool of built in methods.
  • AJAX Capabilities.
  • Methods for changing or applying CSS, creating animations.
  • Event detection and handling.
  • Tons of plug-ins for all kind of needs.

These are just a few reasons. But the bottom line is the jQuery is becoming the standard for DOM manipulation, simple effects, and much more.

  • Well maintained - Documentation, examples, it's all there.
  • Browser compatible - You don't worry about it.
  • Easy to learn - Spend more time coding!
  • Large community - The answer is always on Stack Overflow.
  • It's correct - It does a lot of small things correctly so you don't have to.
  • Extendable - Tons of community plugins for value.

Multithreading in java

Java is a multi-threaded programming language which means we can develop multi-threaded program using Java. A multi-threaded program contains two or more parts that can run concurrently and each part can handle a different task at the same time making optimal use of the available resources specially when your computer has multiple CPUs.

Multithreading in java is a process of executing multiple threads simultaneously.

Thread is basically a lightweight sub-process, a smallest unit of processing. Multiprocessing and multithreading, both are used to achieve multitasking.

But we use multithreading than multiprocessing because threads share a common memory area. They don't allocate separate memory area so saves memory, and context-switching between the threads takes less time than process.

Java Multithreading is mostly used in games, animation etc.


1) It doesn't block the user because threads are independent and you can perform multiple operations at same time.

2) You can perform many operations together so it saves time.

3) Threads are independent so it doesn't affect other threads if exception occur in a single thread.

In this process we execute multiple threads simultaneously.Because thread is basically a lightweight sub-process, a smallest unit of processing.As we know Multiprocessing and multithreading, both are used to achieve multitasking purposes only.But we use multithreading than multiprocessing because threads share a common memory area. They don't allocate separate memory area so saves memory, and context-switching between the threads takes less time than process.And we use multithreading for animation,gaming etc.its major advantage is Threads are independent so it doesn't affect other threads if exception occur in a single thread and it can perform multiple operations at a time and saves our time to.