Use a .jar java library API in C#?

Hello,

I'm an entry level programmer so please bear with me and be descriptive in your responses.

I am trying to use a Java API given as a .jar file in my C# .net application. I don't know much Java, but this .jar file says "no main-class manifest attribute" when I try to run it so this means its a library? This Java API also comes with a .java file which shows how to use the library but I cannot see the code inside the .jar.

I found this question on this site, and one of the answers reads, "In simple way you can pack your java classes to jar file then In C# use Process class for execute and map IO stream." I am semi-familiar with the Process class in C# but I don't understand how I could use it to use a Java library in my C# .net project.

Is this possible? or was that answer incorrect?

If so, could you explain how I can use the .jar library in my C# app.

Thanks in advance.

From stackoverflow timmyg

• You can't load a Java library in a C# project without at least some sort of marshaling layer. To my knowledge, no such product exists.

  The previous question's answer describes how to start a Java executable from within C#. It won't work for libraries.

  mikerobi : You really should delete this answer, read the accepted answer and you will see why,
  From Jekke

• You can do it using IVKM.Net. IVKM.NET includes an application called ikvmc. Here’s the documentation for this tool:

  http://www.ikvm.net/userguide/ikvmc.html

  To use it compile your java code into a Jar. Then run the ikvmc program:

  ikvmc myCode.jar

  If your jar contains a main() function it will be converted into an exe that can be run on the CLR. Otherwise it will be converted into dll’s. To use the dll’s in your project just add them as references in Visual Studio and the same API that was available to you in Java will be accessible in your .Net application.

  You can also include the IKVM.GNU.Classpath.dll dll from ikvmc and use the standard java class libraries in tour application.

  Here's a blog post I made about it: http://www.codestrider.com/BlogRead.aspx?b=caabb788-6206-451a-acb4-9b5f12565922

  timmyg : thanks I will give it a try. once i have the .dll and I import it into my project should I call the library's function using Pinvoke?

  scurial : You don't need to use pinvoke. You should be able to simply call the api just like you would as if it was orig written in C#.

  LDomagala : you should change "run on the CIL" into "run on the CLR"

  timmyg : It Worked! Thanks again!

  scurial : oops, good call CIL ==> CLR ... it should run on the runtime

  Cragly : Good stuff, just used it in my .net app and worked like a charm. Thanks
  From scurial

• Have a look at IKVM ... it has tools to give you some level of interop. When you say Java API I assume you want to call some functionality from the jar rather than just execute it

  timmyg : Correct, the .jar doesn't execute, it reports an error message that reads, "Failed to load Main-Class manifest attribute from ...". Once I have the .jar converted to .dll I'm going to attempt to use it the same as the java coded example using the .jar.
  From Conrad