List employeeList = getEmployeesFromDataSource();
Predicate isEmployeeActive = e -> e.getStatus() == EmployeeStatus.ACTIVE;
String result = employeeList.stream()
                .filter(isEmployeeActive)
                .map(e -> e.getId().toString())
                .collect(Collectors.joining(",", "[", "]"));
         
        System.out.println("Active employees = " + result);