Q217. What is the difference between an if statement and a switch statement?
The if statement is used to select among two alternatives. It uses a boolean expression to decide which alternative should be executed. The switch statement is used to select among multiple alternatives. It uses an int expression to determine which alternative should be executed.

Q218. What happens when you add a double value to a String?
The result is a String object.

Q219. What is the List interface?
The List interface provides support for ordered collections of objects.