[Java] CollectionsUtils.sort

ArrayList<Employee> employees = getUnsortedEmployeeList();
Comparator<Employee> compareById = (Employee o1, Employee o2) -> o1.getId().compareTo( o2.getId() );

Collections.sort(employees, compareById); 
Collections.sort(employees, compareById.reversed());



Arrays.stream("a", "b", "c")
    .sorted()
    .collect(Collectors.toList());
Arrays.stream("a", "b", "c")
	.sorted(Comparator.reverseOrder()))
	.collect(Collectors.toList());
    
Arrays.stream("a", "b", "c")
	.sorted(Comparator.reverseOrder()))
    .findFirst()
    .orElse(null);

 

[출처] 

https://howtodoinjava.com/sort/collections-sort/

https://stackoverflow.com/questions/33487063/java-8-sort-list-of-objects-by-attribute-without-custom-comparator

https://stackoverflow.com/questions/28607191/how-to-use-a-java8-lambda-to-sort-a-stream-in-reverse-order