Immutable and generics

Questions 1 to 5 of 7

1. 1. What happens when this program runs? ``java import java.util.Map; public class Main { public static void main(String[] args) { Map<String, Integer> m = Map.of("a", 1, "a", 2); System.out.println(m); } } ``

   It prints {a=2}, because the second value replaces the firstIt prints {a=1}, because the first value winsIt throws IllegalArgumentException with the message duplicate key: aIt throws UnsupportedOperationException, because maps made with Map.of cannot be printed
2. 2. Why does o instanceof List<String> fail to compile in Java, when o is declared as Object?

   Java has no instanceof operator for interface types such as ListAt run time the check can see only List, not the String in the brackets, because erasure removed itObject cannot be used on the left side of instanceofA List can only be checked against an array type
3. 3. True or False: After Collections.unmodifiableList(backing) is made, adding an item to backing makes that new item visible through the view.

   False, because Collections.unmodifiableList makes a copy when it is calledTrue, because the unmodifiable list is a read-only view that reads the original list, so it shows later changes
4. 4. True or False: In C++, larger<int> and larger<double> are two separate functions in the compiled program, so each one has its own static variable.

   True, because each type used gets its own copy of the template, and each copy has its own static variableFalse, because one function serves all types, so the static variable is shared
5. 5. What is wrong with this program? ``cpp #include <iostream> #include <map> #include <string> int main() { const std::map<std::string, int> stock{{"pen", 2}}; int n = stock["pin"]; std::cout << n << '\n'; } ``

   The #include <map> line is missing, so std::map is unknownstock["pin"] is refused on a const map, because [] can insert a missing key; use at to read the valueA const map cannot use std::string keysThe variable n must be declared as const int