I need another help in Java

[maroon1]

Can someone tell me how to input an integer and make it display as 6 digit number ?

For example if ID = 4, it should display as 000004

Also, I have another question. I want to write a function that check if the the string representing the Email of a person is a valid format or not. It should check if the Email have an @ and a dot. Can someone tell me how ?

Thanks in advance.