Added code for sorting

src/main/java/com/nisum/example/client/ClientApp.java

@@ -10,37 +10,49 @@ import java.util.stream.Collectors;
  */
 public class ClientApp {
     public static void main(String[] args) {
-        Person p1= new Person(1201,"HARI",8700,"HYD","DEV","40582678416578",
+        Person p1= new Person(1201,"HARI",8700,"HYD","DEV",20200725122530L,
                 Arrays.asList("7722448815","9966778844","9944668877"));
         Person p2= new Person
                 (1202,"SHAM",5500,"PUNE","QA",
-                        "69382678416578", Arrays.asList("8855447788","7547871478","0147248784"));
+                        20201025013020L, Arrays.asList("8855447788","7547871478","0147248784"));
         Person p3= new Person
                 (1203,"SAI",7500,"BANGLORE","DEV",
-                        "14782678413689", Arrays.asList("7755447788","6767714785","01452487845"));
+                        20200825032515L, Arrays.asList("7755447788","6767714785","01452487845"));
         Person p4= new Person
                 (1204,"KIRAN",9500,"CHENNAI","DEV",
-                        "89782678413689", Arrays.asList("8855447788","7667714785","01252487845"));
+                        20201125052010L, Arrays.asList("8855447788","7667714785","01252487845"));
         Person p5= new Person
                 (1203,"KHAN",4500,"CHENNAI","PROD",
-                        "60582678413689", Arrays.asList("9955447788","1467714785","02352487845"));
+                        20200625072045L, Arrays.asList("9955447788","1467714785","02352487845"));
 
-        List<Person> persons=Arrays.asList(p1,p2,p3,p4,p5);
+        List<Person> personList=Arrays.asList(p1,p2,p3,p4,p5);
 
         // find the person id with highest salary in a given department
-       Optional<Person> optionalPerson= persons.stream().filter(p -> p.getDepartment().equals("DEV"))
-                .collect(Collectors.maxBy(Comparator.comparingInt(f-> f.getSalary())));
-       System.out.println
-               (optionalPerson.isPresent()?
-                       "Person ID with highest salary :"+optionalPerson.get().getId():
-                       "Record with highest salary not exist");
-
-
-       // print the no of employees at each location.
-      Map<String,Long> locationCount= persons.stream().collect(Collectors.groupingBy(Person::getLocation,Collectors.counting()));
-      for(String s:locationCount.keySet()){
-          System.out.println(s+"-"+locationCount.get(s));
-      }
+      Optional<Person> highestPaidPersonWrapper=  personList.stream()
+              .filter(p-> p.getDepartment().equals("DEV")
+              ).collect(Collectors.maxBy(Comparator.comparingInt(f-> f.getSalary())));
+
+      System.out.println("Highest Salary Person ID: "+highestPaidPersonWrapper.get().getId());
+
+      //print the no of employees at each location.
+        Map<String,Long> personCountByLocation=personList.stream()
+                .collect(Collectors.groupingBy(Person::getLocation,Collectors.counting()));
+
+        Set<Map.Entry<String,Long>> entrySet=personCountByLocation.entrySet();
+        for(Map.Entry<String,Long> entry:entrySet){
+            System.out.println(entry.getKey()+" "+entry.getValue());
+        }
+
+        //verify the two persons provided the same phone number
+
+        //sort the person list based on timestamp.
+        //sort descending
+       List<Person> sortBasedOnTimestamp= personList.stream()
+               .sorted(Comparator.comparing(Person::getTimestamp).reversed()).collect(Collectors.toList());
+       sortBasedOnTimestamp.forEach(System.out::println);
+
+
+
 
     }
 }

src/main/java/com/nisum/example/model/Person.java

@@ -19,6 +19,6 @@ public class Person {
     private int salary;
     private String location;
     private String department;
-    private String timestamp;
+    private long timestamp;
     private List<String> phones;
 }