I think the point here is being missed slightly - it's not just about the aspects of the language and the APIs you know, it's also about being able to use and understand good design principles, design patterns and all round decent OO. On top of that being able to understand the needs of the business for which you are developing and being able to challenge approaches where necessary is a big bonus. Obviously being able to code the thing is important but there is too much emphasis on the language itself.