There are two fields in Java.lang.System, in and out - that are keywords in C# language. In IKVM.GNU.!Classpath.dll they have been renamed to @in and @out respectively. We rename those in VirtualizationMode.

[Java]

public class Test
{
    public void Method()
    {
        System.out.print("Text");
    }
}

[C#]

public class Test
{
    public void Method()
    {
        System.@out.print("Text");
    }
}