I want to upgrade my Ubuntu 10.10 to 11.04. At the same time, I don’t want to lose my applications. Is there a way to do so?
No, upgrading Ubuntu won't cause you to lose your programs and or documents. However, I wouldn't upgrade unless there was a clear incentive to do so, why do you want to upgrade? (Security updates? Better GUI?) As a general rule, don't fix whats not broke.