I have converted a C# file into jar. I would like to use it in a Java Web application using Spring. I'm currently using Intellej. My current problem, is I don't know how to let tomcat uses the IKVM.NET Virtual Machine environment and also intellej for that to work.
IKVM is dead. There is never which maintenance it since years.
IKVM is also for converting a jar file to a .NET dll and not inverse. It is not possible to use a jar file created with IKVM at runtime. This are only stub files for the Java compiler.
If you want use Tomcat with IKVM then you need to convert all jar files of Tomcat to a dll. For debugging then you need to use a C# IDE like Visual Studio and not IntelliJ.
If you want use a C# file with Java then the GraalVM can be a solution but I have never try it.