sample11.java

import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;



public class sample11 {
 public static ArrayList<Integer> getKeys(LinkedHashMap<Integer, String> linkedHashMap) {
 Set<Integer> keySet = linkedHashMap.keySet();
 ArrayList<Integer> keys = new ArrayList<>();
 ArrayList<String> values = new ArrayList<>();
 for (Integer key : keySet) {
 String value = linkedHashMap.get(key);
 values.add(value);
 }

 String dup = "";
 for (String str: values) {
 if (Collections.frequency(values, str) > 1 && !str.equals(dup)) {
 dup = str;
 for (Map.Entry<Integer, String> entry: linkedHashMap.entrySet()) {
 if (entry.getValue().equals(str)) {
 keys.add(entry.getKey());
 }
 }
 }
 }

 return keys;
 }

 public static void main(String[] args) {
 LinkedHashMap<Integer, String> hm = new LinkedHashMap<>();
 hm.put(105, "Rajnish");
 hm.put(103, "Suraj");
 hm.put(101, "Surya");
 hm.put(104, "Siva");
 hm.put(102, "Syam");
 hm.put(106, "Surya");

 System.out.println(getKeys(hm));
 }
}