J2N 2.0.0-beta-0017

This is a prerelease version of J2N.
There is a newer version of this package available.
See the version list below for details.
Install-Package J2N -Version 2.0.0-beta-0017
dotnet add package J2N --version 2.0.0-beta-0017
<PackageReference Include="J2N" Version="2.0.0-beta-0017" />
For projects that support PackageReference, copy this XML node into the project file to reference the package.
paket add J2N --version 2.0.0-beta-0017
The NuGet Team does not provide support for this client. Please contact its maintainers for support.
#r "nuget: J2N, 2.0.0-beta-0017"
#r directive can be used in F# Interactive, C# scripting and .NET Interactive. Copy this into the interactive tool or source code of the script to reference the package.
// Install J2N as a Cake Addin
#addin nuget:?package=J2N&version=2.0.0-beta-0017&prerelease

// Install J2N as a Cake Tool
#tool nuget:?package=J2N&version=2.0.0-beta-0017&prerelease
The NuGet Team does not provide support for this client. Please contact its maintainers for support.

J2N - Java-like Components for .NET

GitHub Sponsors

J2N is a library that helps bridge the gap between .NET and Java.

Our Goals

  • Java-like behaviors
  • .NET-like APIs
  • Be the defacto library to use when porting from Java to .NET
  • Provide high quality, high performance components that can be used in a wide range of .NET applications

Basically, if you are looking for a "JDK.NET", this is about as close as you can get. While we recommend using purely .NET components where possible when porting from Java, there are some Java features that have no .NET counterpart or the .NET counterpart is lacking behaviors that are not easy to reproduce without reinventing the wheel. Even if you prefer to reinvent the wheel by designing your own ".NETified" component, you may still need a Java-like component to compare your component against in tests.

That is why we created J2N. If you like this idea, please be sure to star our repository on GitHub.

Our Focus

  1. Text analysis: code points, normalizing behaviors between different "character sequence" types, tokenizing, etc.
  2. I/O: Reading and writing types in both big-endian and little-endian byte order and providing specialized behaviors for interop with Java-centric file formats.
  3. Collections: .NET's cupboard is a little bare when it comes to specialized collections, so we fill in some gaps.
  4. Equality: Compare collections for structural equality with behaviors that are specific to each collection family, and provide .NET equality comparers for other types that differ in behavior.
  5. Localization: Bridge the gap between .NET's culture-aware and Java's culture-neutral defaults.

Status: Beta

Much of what is here has been tested pretty thoroughly already and the APIs are pretty stable. We anticipate the beta period to be quite short.


Install-Package J2N -Pre


We love getting contributions! If you need something from the JDK that we don't have, this is the right place to submit it. Basically, the following are things that would be a good fit for this library:

  1. Components in the JDK that have no direct counterpart in .NET, or the counterpart is lacking features
  2. Features that make J2N easier to work with in .NET such as extension methods and adapters
  3. Features that make .NET interoperate with Java better (i.e. load Java-proprietary file formats, string formats, etc.)

Please base your contribution on the release/v2.0 branch and target this same branch when you submit the PR (note that GitHub has no way to re-target a PR to another branch, so this is important).

Saying Thanks

If you find this library to be useful, please star us on GitHub and consider a sponsorship so we can continue bringing you great free tools like this one. It really would make a big difference!

GitHub Sponsors

NuGet packages (12)

Showing the top 5 NuGet packages that depend on J2N:

Package Downloads

Lucene.Net is a full-text search engine library capable of advanced text analysis, indexing, and searching. It can be used to easily add search capabilities to applications. Lucene.Net is a C# port of the popular Java Lucene search engine framework from The Apache Software Foundation, targeted at .NET Framework and .NET Core users.


Replicator that allows replication of files between a server and client(s) for the Lucene.Net full-text search engine library from The Apache Software Foundation.


ICU (International Components for Unicode) is a set of libraries providing Unicode and Globalization support for software applications. It provides Text-boundary analysis (RuleBasedBreakIterator) as well as easy access to all of the many Unicode character properties, Unicode Normalization, Case Folding and other fundamental operations as specified by the Unicode Standard. ICU4N is a .NET port of ICU4J.


Japanese Morphological Analyzer for the Lucene.Net full-text search engine library from The Apache Software Foundation.


RandomizedTesting.Generators contains generators for random numbers, several forms of text (ASCII, Unicode, realistic Unicode, HTML-like, regular expression-like) as well providing methods to pick random selections from collections and arrays and even create randomly generated Regex classes. These features are implemented as simple low-level extension methods to for the Random class so there is very little to learn to quickly generate random data for your tests. Why would you want tests to have random data? This is to fill situations where it is not practical to test the entire range of values in a single test run, for example, with applications that analyze text. Tests can instead be designed to provide different input every time they run to catch edge cases that are difficult to test for. Generating random data also has many other purposes, such as quickly generating a set of text files to benchmark with without having to store several hundred MB worth of files (since the same random seed will always generate the same data).

GitHub repositories (2)

Showing the top 2 popular GitHub repositories that depend on J2N:

Repository Stars
Apache Lucene.NET
🌐 YAF.NET - C# ASP.NET Forum
Version Downloads Last updated
2.0.0 124 1/15/2022
2.0.0-beta-0017 26,947 10/24/2021
2.0.0-beta-0016 7,003 7/24/2021
2.0.0-beta-0015 4,355 4/25/2021
2.0.0-beta-0014 60 4/24/2021
2.0.0-beta-0013 859 4/20/2021
2.0.0-beta-0012 313,151 3/10/2021
2.0.0-beta-0011 7,260 12/3/2020
2.0.0-beta-0010 172,390 9/21/2020
2.0.0-beta-0009 74,867 7/27/2020
2.0.0-beta-0008 40,036 7/11/2020
2.0.0-beta-0007 138,656 3/28/2020
2.0.0-beta-0002 8,854 2/7/2020
2.0.0-beta-0001 555 1/23/2020
1.0.0-beta-0002 5,817 12/28/2019
1.0.0-beta-0001 274,645 12/23/2019
1.0.0-alpha-0030 429 12/13/2019
1.0.0-alpha-0017 406 12/2/2019