Question

Create a class “MapIntersectClient” and write a method
mapIntersect in that class that accepts two maps whose keys are strings and whose values are integers as parameters and returns a new map containing only the key/value pairs that exist in both of the parameter maps. In order for a key/value pair to be included in your result, not only do both maps need to contain a mapping for that key, but they need to map it to the same value. For example, if the two maps passed are {Janet=87, Logan=62, Whitaker=46, Alyssa=100, Stefanie=80, Jeff=88, Kim=52, Sylvia=95} and {Logan=62, Kim=52, Whitaker=52, Jeff=88, Stefanie=80, Brian=60, Lisa=83, Sylvia=87}, your method would return the following new map (the order of the key/value pairs does not matter): {Logan=62, Stefanie=80, Jeff=88, Kim=52}.
Please write main method inside this class and create , initialize maps and pass them to the mapIntersect method and print the returned map.

Answer 1

Answer:

import java.util.*;
public class MapIntersectClient {

public static void main(String[] args) {
HashMap<String, Integer> m1 = new HashMap<String, Integer>();//declaring map-1 varaibles
   m1.put("Janet", 87);
m1.put("Logan", 62);
m1.put("Whitaker", 46);
   m1.put("Alyssa", 100);
   m1.put("Stefanie", 80);
   m1.put("Jeff", 88);
   m1.put("Kim", 52);
   m1.put("Sylvia",95);
HashMap<String, Integer> m2 = new HashMap<String, Integer>();//declaring map-2 vraibles
   m2.put("Logan", 62);
m2.put("Kim", 52);
m2.put("Whitaker", 52);
   m2.put("Jeff", 88);
   m2.put("Stefanie", 80);
   m2.put("Brian", 60);
   m2.put("Lisa", 83);
   m2.put("Sylvia",87);
System.out.println(mapintersect(m1,m2));//calling calling function mapintersect
}
public static Map mapintersect(Map a,Map b)
{
Map m2 = new HashMap(); //intialising new map to return after completion
Iterator<String> it = a.keySet().iterator(); //creating itearator for map-a
while (it.hasNext()) {//looping through map-a values
Iterator<String> it1 = b.keySet().iterator(); //creating itearator for map-b
String key = it.next();
while(it1.hasNext()) //looping through map-b values
{
String key2 = it1.next();
if(key2.equals(key) && (a.get(key)==b.get(key2))) //comparing map-a values with map-b
{
m2.put(key,a.get(key));//inserting into map-2 if equal
}
}

}
return m2;//returning map-2
}

}

Output:

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