Singleton vs Static class : Key Differences and Usages

The debate about Singleton vs Static is quite old and it is still continuing and there are lots of confusion around this as well. In this post, I am trying to explain these two concepts, key differences and its usages.In this post I will not focus on the basics of Static and Singleton and how to write that. If you are new to these keywords, I will advise you to learn about these first to get more benefited.

So first we are going to understand the characteristics of each . Lets start with static class

Static Class :

  1. Static classes cannot be instantiated so it restricts us in many ways like it cannot implement Interfaces, inherit any class etc.
  2. Any other scenarios where this keyword is required, it cannot be used like indexer etc. Also it cannot be used as method parameter, local variable etc for the same reason.
  3. Static classes can have only static members – constructor, fields, methods, properties, events.
  4. One cannot control when static constructors are called. It’s always earlier than first access of the class. So no parameters can be passed as well.

Internally when compiler compiles static class, it marks it as a abstract and sealed. So that no instance can be created and cannot be extended as well. Now let’s talk about Singleton

Singleton Class :

  1. As name suggests it allows to have only one instance of a class.
  2. The constructor of this class are marked as private so that accidentally one cannot create multiple instances and provides a static function/property which first create one instance and returns the same each time.
  3. As singleton is a normal class, it allows us to leverage all that features of object oriented programming concepts.

Memory Management :

There is much confusion around memory management of static class and Singleton class. In simple words, any class whether it is itself static or any member if marked as static then it would not be collected by Garbage Collector.

Static variables/classes are not stored in normal Heap and there is a separate space in memory to store static resources which holds the static classes and variables.This space is beyond the scope of GC and memory get release only when corresponding process/AppDomain unloads.

Because singleton holds a static reference which cannot be collected by GC so the instance cannot be collected and both (Static and Singleton) gets destroyed with the AppDomain/Process.

Some Key common characteristics :

  • As both of the static and singleton instances are have just one copy in memory throughout the whole application, both used for holding global state in an application.
  • Both are initialized lazily, it means for static classes it is initialized only when accessed first time and for Singleton, it gets created only when it is accessed first time.

The Differences

  1. Very first difference is that Static is a language feature and Singleton is a architectural pattern so both belongs to difference arena altogether.
  2. Now a days everybody is behind using Dependency Injection and Static does not fit there because it is interface driven.
  3. Unit Testing is another topic where you can find some way to create a mock for singleton instances but testing static is a nightmare.
  4. Being singleton is a just another class, it enable you to use Object oriented concepts.

Singleton approach is much more flexible as we can see that from the differences itself. We can use interface with it and implement it in a class and use in our application. If some requirement changes and later we require to change the logic then we can just remove the older implementation and replace with new one without hiccups as long as the interface is same.. Also testing is another key benefit.

Static classes is mainly recommended for having grouping of a bunch of utility methods that can be called independently but again testing could be a problem and benefits of OOP is gone. So most of the time static should be avoided.

Having said that using global variable (like static class or singleton) makes a strong coupling between the global data and all the places where it is used.



Top 12 tricks to insert common code snippets : Productivity Tips

This post is in line with my previous post where I talked about how one can be more productive with Visual Studio. In last post, We discussed top 12 shortcuts that helps a lot while writing and reviewing code in day to day work. While writing code we need to follow to follow certain rules and constructs that also becomes very repetitive say, you are writing classes for your domain or adding properties or defining constructors or putting try block and lot more where we just need to write the code in similar pattern and are no brainer. Spending time in these types of code are kind of waste of time and energy. To see my previous post, use the link below

Top 12 Visual Studio short cuts – Productivity Tips

In this post, I am going discuss 12 tricks that can insert code snippets just by few keystrokes.

1- Writing a class is a one of the most common repetitive code we write. Use

  class press TAB





Once the snippet inserted, it puts the cursor at MyClass which allows to change the name of class instantly without any extra keystroke.

2- Writing constructor is also another task which is very common and many times we many constructor for the same class. To write constructor use

ctor press TAB





3- Now Class is created. Let’s add property now. Use

prop press TAB




Similar as 1st trick, it puts the cursor to change the type and after that change the property name itself. I found really cool when I used first.

It comes with many other flavor. Use propg  to create a auto implemented property with private set.

4- Second trick allows us to write auto-implemented property which requires less code but there could be many scenarios, when we need to write Full property definition that we used in earlier to C# 3.0 then use

propfull press TAB






Changing type and name can be done similar to above.

5- Need to write an indexer, use

indexer press TAB





6- Many times while code review we see that some part of code is not under try catch block or we need to write the block. Use

try press TAB






There is another flavor, if we just want try and finally then use tryf.

7- Want to create enum use

enum press TAB





Similarly use struct to insert struct block.

8- Want to create switch block, use

switch press TAB





Similarly use for, foreach, do, while etc to insert respective code blocks.

9- Many times we need to write our own custom exception class that should inherit from Exception class. It can written easily by

Exception press TAB

It creates a serializable class as

8- Exception







10- Want to override Equals method for your class. Use

equals press TAB

It will insert as












11- To write static void main, use

svm press TAB





Similarly you can use sim for static int main.

12 – last, many times we write console.writeline in our application. Just use

cw press TAB



In this post, how can we save lots of keystrokes and time while writing some very common repetive code. This is not complete list but very common ones that can be used a lot in our day to day coding. if you know any other snippet which is very useful, do share in comments.


Top 12 Visual Studio short cuts – Productivity Tips

Visual Studio is very Rich IDE and it provides in-numerous features that makes our day to day life easy. There are some very useful hot keys and tips which can increase our productivity significantly. Earlier I used few hot keys but recently I learned few which I found awesome which drastically reduce my time while writing/debugging/reviewing the code. So learn these and make a habit of these keys and feel super charged while writing code.

  1. While code review I find many time scattered and unaligned code which I hate. I use CTRL+K+D for aligning it.
  2. While debugging or testing the code, commenting/commenting codes are done a lot. Use CTRL+K+C/CTRL+K+U for the same.
  3. How do you up/down certain line of code. Select the code block and use ALT+up/down
  4. You have a used a lot F12 to go to Definition of class. Use CTRL – to go back.
  5. How do you resolve the classes by mouse click. Use CTRL+. to resolve it quickly.
  6. Refactoring is very important. Use CTRL+R+M for extracting a method.
  7. Find All References -> Use Shift + F12. Very helpful while debugging and fixing bugs.
  8. Want to put few lines of code in try block. Try Ctrl + K + S, it provides lot more options
  9. Ever tried selecting a rectangle code. Use ALT click drag.
  10. Lots of code in a single file. Use  CTRL + M + O and CTRL + M + X in collapse/expand code groups like regions, methods etc.
  11. Lots of code and there are no groups. Use CTRL+M+H/CTRL+M+U
  12. Another super sweet. ALT+F4 to close the window.

Try using the above in your day to day coding and be more productive.



12 tips to increase the performance of ASP.NET application drastically – Part 2

This post is second part of my previous post where we discussed six tips to improve the performance of ASP.NET applications. In this post, we are going to discuss six more tips that could be another round a booster for your application performance. The link of previous post is below.

12 tips to increase the performance of ASP.NET application drastically – Part 1

  1.   Make your page asynchronous

IIS uses CLR thread pool to get a thread that processes a request that comes to the application. Say, if there are currently twenty threads available in pool, it means only twenty request can be served in parallel and if request processing takes some time then it could turn into disaster if hundred odd request are bombarded in few milliseconds. In this case…Read complete post on Infragistics blog

Routing not working when upgrading Angular library to 1.4 : Solution

I wrote a lot about AngularJS (18 articles till date) but recently I was working on a project where we upgraded the AngularJS library from 1.0 to 1.4 and found that many functionalities stopped working. Routing was one major part and one of my team member rushed me for a solution and then I realized the amount of changes.

One of the major changes, Routing is not part of the main Angular library and it needs to be added as external module. And we need to inject ngRoute if we want to use it. This changes took place in v1.2. In this post, I am considering that we are upgrading from 1.0.* to 1.4.* . I am taking example of one of my previous posts and upgrade that here. Both old and updated solution is attached. Let’s have a look again on the example screen

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Asynchronous programming with async and await : explained

In one of my previous posts, I discussed about the synchronous and asynchronous programming model. We saw in details that how does it work in single and multi-threaded mode. This post is extension of that post and here we are going to discuss the two relatively new keyword async and await and how does that actually work. I got many questions around this so sharing it in details here. If you are not very clear about how synchronous and asynchronous programming works and how does it work in single and multi-threaded scenario then refer my previous post mentioned below.

Concurrency vs Multi-threading vs Asynchronous Programming : Explained

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12 tips to increase the performance of ASP.NET application drastically – Part 1

Building web application and hosting it on a web server is insanely easy with ASP.NET and IIS. But there are lots of opportunities and hidden configurations which can be tweaked that can make it high performance web application. In this series post, we are going to discuss some of the most unused or ignored tricks which can be easily applied to any web application.

  1. Kernel mode cache – It is one of the primary tools widely used for writing making web application faster. But most of the times, we don’t use it optimally and just leave some major benefits. As each request goes through various stages, we can implement caching at various level as belowcachingoppWe can see that request is first received by http.sys so if it is cached at kernel level, then we can save most of the time spent on server as http.sys is a http listener which sits in OS kernel…Read complete post on Infragistics blog