Use Java library in C# - IKVM.NET

[1] IKVM.NET
[2] http://en.wikipedia.org/wiki/IKVM.NET

From [2]:

IKVM.NET is an implementation of Java for Mono and the Microsoft .NET Framework. IKVM is free software, distributed under a permissive free software licence.[1]

IKVM.NET includes the following components:

    A Java Virtual Machine implemented in .NET
    A .NET implementation of the Java class libraries
    A tool that translates Java bytecode (JAR files) to .NET IL (DLLs or EXE files).
    Tools that enable Java and .NET interoperability

With IKVM.NET you can run compiled Java code (bytecode) directly on Microsoft .NET or Mono. The bytecode is converted on the fly to CIL and executed.

Therefore if you want to use a java Jar library as C# assembly, you can use IKVM for the conversion.

This is great.