In some projects, there are types, which have same name with some library types. For using both of them in a class, you should import library type and qualify project type reference with package name. It is opposite in C# so we qualify library type usages with namespace.

Suppose Calender is a project type:

package Test;
public interface Calendar
{
    //some code
}

And in another classes of project, we want to use both this interface and java.util.Calendar:

package Test;
import java.util.Calendar;
public class MyCalendar
{
    Test.Calendar projectCalendar;
    Calendar libraryCalendar;
}

It should be translated like below (Supposed we are in VirtualizationMode so java.util.Calendar is available):

namespace Test
{
    public class MyCalendar
    {
        Test.Calendar projectCalendar;
        java.util.Calendar libraryCalendar;
    }
}