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How to Build OmegaT from Source Code

Compile OmegaT from the source codeHave you ever wanted to get a new version of OmegaT, yet the final release was weeks or months away?

If you have, then this article is for you. There’s a rumor that the upcoming version 3.0 will contain an array of powerful features such as tag-related improvements. But no one knows the release date. So why wait? Simply download the latest source code to compile OmegaT yourself!

Note: This procedure is for Windows users. All file and folder paths are examples only. Replace them as appropriate. I also recommend doing it on a computer other than your “production” machine.



Since OmegaT is written in Java, JDK is required to compile it.

    1. Download and install JDK, e.g. to c:Program FilesJavajdk1.7.0_21.
    2. Open the command prompt and run:

set JAVA_HOME=c:Program FilesJavajdk1.7.0_21

This is required to switch the regular JRE to JDK.


Ant is a program designed to build Java applications from the source code.

  1. Download ant from
  2. Unzip to c:Program Filesapache-ant-1.9.0.

Getting and building from the source code

  • Go to the OmegaT’s source code page.
  • Click Download Snapshot.
  • Wait until SourceForge generates a source code snapshot and save it to a temporary location.
  • Unzip it. You’ll get omegat-svn-XXXX.tmp.
  • Unzip this TMP file as well. It includes three folders, but you only need the trunk folder. Unzip it to c:Program FilesOmegaTtrunk.
  • In the command prompt, run:

    cd c:Program FilesOmegaTtrunk
    “C:Program Filesapache-ant-1.9.0binant” jar release

  • Watch for any errors. If you get any and can’t resolve them, feel free to post them in the comments here.
  • The program will be compiled in the c:Program FilesOmegaTtrunkdist subfolder. To run it, run OmegaT.jar. You can also copy OmegaT.exe and OmegaT.l4J.ini from the installation folder to this folder and launch OmegaT.exe.

A useful resource on this topic is Marc Prior’s article about compiling OmegaT from the source code, which also includes a few examples of making changes to the source code to customize the program.

And why would you want to build OmegaT from the source code? Perhaps, you like to have certain things your way? Do tell us in the comments!


  • Jean-Christophe Helary says:

    In fact, building OmegaT from source is so easy that everybody should give that try. Because *that* is what free software really means.

    Searching on the web will help you find automated ways to download OmegaT’s source code, then, you mix that with an automated build and here you go: always the latest of the code. You can check in the changes.txt which new feature has been documented (some are not documented right away as they are included in the code).

    Building the code oneself is the first step toward actively contributing to a free software project. Go ahead. We’re waiting for you on the other side of the fence ! 🙂

    • Hi Jean-Christophe!
      Thank you so much for your comment!
      Nothing I can add really 🙂
      Yours sincerely,

    • Nina says:


      Acctually, I download OmegaT’s code source but i don’t know where can i modify it or changue somethings, and i even don’t know if i should open it with netbeans or another program. I’m really blocked and i need it for my studies.

      Please can you help me

  • Людвиг says:

    Такой вопрос. Есть скрипт, который создает билингв файл (“Unclean”), аналогично Trados. Единственный минус, что процент совпадения “Match” в нем фиктивный – везде “0”.
    Возможно ли реализовать в OmegaT извлечение реальных значений процента совпадения?

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Roman Mironov
Roman Mironov
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As the founder of Velior, Roman has had the privilege of being able to turn his passion for languages into a business. He has over 15 years of experience in the translation industry. Roman has helped dozens of clients increase sales by making their products appealing for speakers of other languages.