ask java experts

supose i have a text field in java (like in gmail home page u have username field ) so i want to fill that field automatically by taking record from the database so is there any mechanism in java to handle this problem????

Does the experts here have to show any credentials or can anyone claim to be an expert. If you are an expert in one field does it make one an expert in all fields? Most explain that their answers are opinions only but if a non expert answers with an opinion it's not such a good thing at times. Does...