text: Q:
  
  Filtering on Java 8 List
  
  I have a list of type List in functional java using List type provided by fj.data.List
  import fj.data.List
  
  List<Long> managedCustomers
  
  I am trying to filter it using the following:
  managedCustomers.filter(customerId -> customerId == 5424164219L)
  
  I get this message
  
  According to documentation, List has a filter method and this should work 
  http://www.functionaljava.org/examples-java8.html
  What am I missing?
  Thanks
  
  A:
  
  As already pointed out in the comment by @Alexis C 
  managedCustomers.removeIf(customerId -> customerId != 5424164219L);
  
  should get you the filtered list if the customerId equals 5424164219L.
  
  Edit - The above code modifies the existing managedCustomers removing the other entries. And also the other way to do so is using the stream().filter() as - 
  managedCustomers.stream().filter(mc -> mc == 5424164219L).forEach(//do some action thee after);
  
  Edit 2 - 
  For the specific fj.List, you can use - 
  managedCustomers.toStream().filter(mc -> mc == 5424164219L).forEach(// your action);
  
  A:
  
  What you did seem a bit weird, Streams (to use filter) are commonly used like this (I don't know what you really want to do with the filtrate list, you can tell me in the comment tp get a more precise answer) : 
  //Select and print
  managedCustomers.stream().filter(customerId -> customerId == 5424164219L)
                           .forEach(System.out::println);
  
  //Select and keep
  ArrayList<> newList = managedCustomers.stream().filter(customerId -> customerId == 5424164219L)
                           .collect(Collectors.toList());
  
  