Which of the follwoing is not true about hashmap?a)It may have a single null key and multiple null values.b)It does not contain unique elements.c)HashMap contains value based on the key.d)It works on the principle of hashing.e)HashMap does not maintain order while iterating.

Is the implementation of Map, which doesn't maintain any order.a)linkedhash mapb)hashmapc)treemapd)liste)map

What is true about HashMap as a collection type?This collection type can contain duplicate values.If a value is added to this collection type that exists, it will not be checked first.This collection type uses index values to track data.This collection type uses key-value pairs to track data.

What differences exist between HashMap and Hashtable?

What happens when you put a key-value pair in a HashMap where the key already exists?

What is the output of the following code?import java.util.*;public class Main { public static void main(String[] args) { Map map = new HashMap<>(); map.put("A", 1); map.put("B", 2); map.put("C", 3); for (Map.Entry entry : map.entrySet()) { if (entry.getValue() == 2) { map.remove(entry.getKey()); } } System.out.println(map); }}a){A=1, C=3}b)IllegalArgumentExceptionc){A=1, B=2, C=3}d){B=2, A=1, C=3}e)ConcurrentModificationException