Technology Corner

Home » DotNet » String Pooling in DotNet

String Pooling in DotNet

Enter your email address to follow this blog and receive notifications of new posts by email.

Join 80 other followers

Twitter updates


RSS InfoQ Feeds

  • First Pedestrian Killed by Self-Driving Car
    A pedestrian was killed on Sunday evening in Tempe, Arizona by a self-driving car operated by Uber, the BBC reports. The firm confirmed that the vehicle was traveling in autonomous mode with a safety driver, the only vehicle occupant, behind the wheel during the crash. By Roland Meertens
  • Microsoft Embeds Artificial Intelligence in Windows 10 Update
    The next Windows 10 update opens the way for the integration of artificial intelligence functionalities within Windows applications. Developers will be able to integrate pre-trained deep-learning models converted to the ONNX framework in their Windows applications. By Alexis Perrier
  • Ankyra Presents “Escape”, a Release Automation Tool that Manages Platforms as Logical Components
    Over the last ten years there has been increased focus on infrastructure as code (IaC) tooling, primarily driven by the rise of Infrastructure as a Service (IaaS) and API-driven infrastructure. InfoQ discussed the challenges of homogenising this tooling with Bart Spaans, founder of Ankyra, who is an expert in the domain of infrastructure and release engineer […]
  • Article: Servlet and Reactive Stacks in Spring Framework 5
    Spring Framework 5 supports both traditional servlet-based and reactive web stacks, in the same server application, reflecting a major shift towards asynchronous, non-blocking concurrency in applications. In this article Spring committer Rossen Stoyanchev explores and contrasts both stacks, and explains the range of available choices, and provides guidance f […]
  • Presentation: Elm and Game Development, a Perfect Fit
    Paulo Diniz discusses the Elm architecture, how to use it as functional reactive programming for web game development. By Paulo Diniz
  • Google Releases “Skaffold”, a Tool That Facilitates Continuous Development with Kubernetes
    Google has released Skaffold, an open source command line tool that facilitates continuous development for Kubernetes applications. Skaffold is entering an increasingly crowded space of Kubernetes development automation tooling, including Azure’s Draft, Datawire’s Forge and Weavework’s Flux. By Daniel Bryant
  • Q&A with Marisa Fagen on Security Championship
    Security lead Marisa Fagen recently spoke at QConLondon 2018 about upskilling and elevating engineering team members into the role of Security Champions. We catch up with Fagen and report on her efforts to address contention caused by a scarcity of security professionals. By Rafiq Gemmail
  • GitHub Licensed Aims to Make it Easier to Comply with OSS Licenses
    GitHub Licensed is an open-source tool that aims to simplify the chore of ensuring license soundness and documentation for all dependencies of a GitHub project. By Sergio De Simone
  • Sauce Labs Adds Analytics and Extended Debugging to Continuous Testing Cloud
    At their recent user conference SauceCon, Sauce Labs introduced new capabilities for its continuous testing cloud including test analytics, featuring a dashboard that analyses test results and exposes common failures by browser and operating system, including Android and iOS. By Helen Beal
  • JavaFX and the Future of Java Client Technologies
    Oracle will remove JavaFX, Applets and Java Web Start from the JDK after Java SE 8. Swing and AWT will remain. By Tim Hodkinson


When compiling source code, your compiler must process each literal string and emit the string into the managed module’s metadata. If the same literal string appears several times in your source code, emitting all of these strings into the metadata will bloat the size of the resulting file.To remove this bloat, many compilers (include the C# compiler) write the literal string into the module’s metadata only once. All code that references the string will be modified to refer to the one string in the metadata. This ability of a compiler to merge multiple occurrences of a single string into a single instance can reduce the size of a module substantially. This process is nothing new—C/C++ compilers have been doing it for years. (Microsoft’s C/C++ compiler calls this string pooling.) Even so, string pooling is another way to improve the performance of strings and just one more piece of knowledge that you should have in your repertoire.

CLR automatically does string pooling by maintaining internpool table in assembly metadata but sometimes we need to do it manually using Intern method of string class.

The Intern method uses the intern pool to search for a string equal to the value of any string. If such a string exists, its reference in the intern pool is returned. If the string does not exist, a reference to string is added to the intern pool, then that reference is returned.

Below is code for this:

String s1 = “Neeraj Kaushik”;
String s2 =new StringBuilder().Append(“Neeraj”).Append(” Kaushik”).ToString();
String s3 = String.Intern(s2);
Console.WriteLine(“s1 == ‘{0}’”, s1);
Console.WriteLine(“s2 == ‘{0}’”, s2);
Console.WriteLine(“s3 == ‘{0}’”, s3);
Console.WriteLine(“Is s2 the same reference as s1?: {0}”, (Object)s2 == (Object)s1);
Console.WriteLine(“Is s3 the same reference as s1?: {0}”, (Object)s3 == (Object)s1);


s1 == ‘Neeraj Kaushik’

s2 == ‘Neeraj Kaushik’

s3 == ‘Neeraj Kaushik’

Is s2 the same reference as s1?: False

Is s3 the same reference as s1?: True

In this case a new string created StringBuilder create new instance of string that is not having same reference with S1. So when we intern value of s2 to s3 then s3 and s1 will share same reference.

In automatic case if assign same value to string instances it will refer to same memory reference like below

string a =”neeraj”;
string b= “neeraj”;
bool res= a==b;



Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Blogs I Follow

%d bloggers like this: