private int id;

private String name;

private int salary;

private List<String> phoneNumber;

public EmployeeMap(int id, String name, int salary,List<String> phoneNumber) {

this.id = id;

this.name = name;

this.salary = salary;

this.phoneNumber = phoneNumber;;

}

public int getId() {

return id;

}

public void setId(int id) {

this.id = id;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public int getSalary() {

return salary;

}

public void setSalary(int salary) {

this.salary = salary;

}

public List<String> getPhoneNumber() {

return phoneNumber;

}

public void setPhoneNumber(List<String> phoneNumber) {

this.phoneNumber = phoneNumber;

}

@Override

public String toString() {

// TODO Auto-generated method stub

return this.id + " " + this.name + " " + this.salary+" "+ phoneNumber;

}

public static void main(String[] args) {

List<EmployeeMap> list = Arrays.asList(new EmployeeMap(1, "Deve1", 2000,Arrays.asList("121","456")),

new EmployeeMap(2, "Deve2", 2000,Arrays.asList("122","457")),

new EmployeeMap(3, "Deve3", 2000,Arrays.asList("123","458")));

// name of all employee

List<String> empName = list.stream().map(emp -> emp.getName()).collect(Collectors.toList());

System.out.println("This is normal map empName :"+empName);

List<List<String>> empPhone = list.stream().map(empsphone -> empsphone.getPhoneNumber()).collect(Collectors.toList());

System.out.println("This is normal map empPhone :"+empPhone);

//flat map

List<String> flat = list.stream().flatMap(phone->phone.getPhoneNumber().stream()).collect(Collectors.toList());

System.out.println("this is flat map value :"+flat);

//flat employee name

List<String> flatEmpname = list.stream().flatMap(empname->empname.getPhoneNumber().stream()).collect(Collectors.toList());

}