Since you are asking for lambdas, you can use the following syntax with Java 8:

Date maxDate = list.stream().map(u -> u.date).max(Date::compareTo).get();

or, if you have a getter for the date:

Date maxDate = list.stream().map(User::getDate).max(Date::compareTo).get();

Comparator<User> cmp = new Comparator<User>() {
@Override
public int compare(User user1, User user2) {
return user1.date.compareTo(user2.date);
}
};


Collections.max(list, cmp);

A small improvement from the accepted answer is to do the null check and also get full object.

public class DateComparator {


public static void main(String[] args) throws ParseException {
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");


List<Employee> employees = new ArrayList<>();
employees.add(new Employee(1, "name1", addDays(new Date(), 1)));
employees.add(new Employee(2, "name2", addDays(new Date(), 3)));
employees.add(new Employee(3, "name3", addDays(new Date(), 6)));
employees.add(new Employee(4, "name4", null));
employees.add(new Employee(5, "name5", addDays(new Date(), 4)));
employees.add(new Employee(6, "name6", addDays(new Date(), 5)));
System.out.println(employees);
Date maxDate = employees.stream().filter(emp -> emp.getJoiningDate() != null).map(Employee::getJoiningDate).max(Date::compareTo).get();
System.out.println(format.format(maxDate));
//Comparator<Employee> comparator = (p1, p2) -> p1.getJoiningDate().compareTo(p2.getJoiningDate());
Comparator<Employee> comparator = Comparator.comparing(Employee::getJoiningDate);
Employee maxDatedEmploye = employees.stream().filter(emp -> emp.getJoiningDate() != null).max(comparator).get();
System.out.println(" maxDatedEmploye : " + maxDatedEmploye);


Employee minDatedEmployee = employees.stream().filter(emp -> emp.getJoiningDate() != null).min(comparator).get();
System.out.println(" minDatedEmployee : " + minDatedEmployee);


}


public static Date addDays(Date date, int days) {
Calendar cal = Calendar.getInstance();
cal.setTime(date);
cal.add(Calendar.DATE, days); // minus number would decrement the days
return cal.getTime();
}
}

You would get below results :

 [Employee [empId=1, empName=name1, joiningDate=Wed Mar 21 13:33:09 EDT 2018],
Employee [empId=2, empName=name2, joiningDate=Fri Mar 23 13:33:09 EDT 2018],
Employee [empId=3, empName=name3, joiningDate=Mon Mar 26 13:33:09 EDT 2018],
Employee [empId=4, empName=name4, joiningDate=null],
Employee [empId=5, empName=name5, joiningDate=Sat Mar 24 13:33:09 EDT 2018],
Employee [empId=6, empName=name6, joiningDate=Sun Mar 25 13:33:09 EDT 2018]
]
2018-03-26
maxDatedEmploye : Employee [empId=3, empName=name3, joiningDate=Mon Mar 26 13:33:09 EDT 2018]


minDatedEmployee : Employee [empId=1, empName=name1, joiningDate=Wed Mar 21 13:33:09 EDT 2018]

Update : What if list itself is empty ?

        Date maxDate = employees.stream().filter(emp -> emp.getJoiningDate() != null).map(Employee::getJoiningDate).max(Date::compareTo).orElse(new Date());
System.out.println(format.format(maxDate));
Comparator<Employee> comparator = Comparator.comparing(Employee::getJoiningDate);
Employee maxDatedEmploye = employees.stream().filter(emp -> emp.getJoiningDate() != null).max(comparator).orElse(null);
System.out.println(" maxDatedEmploye : " + maxDatedEmploye);

LocalDate maxDate = dates.stream()
.max( Comparator.comparing( LocalDate::toEpochDay ) )
.get();


LocalDate minDate = dates.stream()
.min( Comparator.comparing( LocalDate::toEpochDay ) )
.get();

troubleshooting-friendly style

You should not call .get() directly. Optional<>, that Stream::max returns, was designed to benefit from .orElse... inline handling.

If you are sure your arguments have their size of 2+:

list.stream()
.map(u -> u.date)
.max(Date::compareTo)
.orElseThrow(() -> new IllegalArgumentException("Expected 'list' to be of size: >= 2. Was: 0"));

If you support empty lists, then return some default value, for example:

list.stream()
.map(u -> u.date)
.max(Date::compareTo)
.orElse(new Date(Long.MIN_VALUE));

CREDITS to: @JimmyGeers, @assylias from the accepted answer.

Just use Kotlin!

val list = listOf(user1, user2, user3)
val maxDate = list.maxBy { it.date }?.date

self-explanatory style

import static java.util.Comparator.naturalOrder;
...


list.stream()
.map(User::getDate)
.max(naturalOrder())
.orElse(null)          // replace with .orElseThrow() is the list cannot be empty