Code reuse: returning lists of enum fields with common getter methods

This is probably one of the cases where you need to pick one between being DRY and using enums.

Enums don't go very far as far as code reuse is concerned, in Java at least; and the main reason for this is that primary benefits of using enums are reaped in static code - I mean static as in "not dynamic"/"runtime", rather than static :). Although you can "reduce" code duplication, you can hardly do much of that without introducing dependency (yes, that applies to adding a common API/interface, extracting the implementation of asListString to a utility class). And that's still an undesirable trade-off.

Furthermore, if you must use an enum (for such reasons as built-in support for serialization, database mapping, JSON binding, or, well, because it's data enumeration, etc.), you have no choice but to duplicate method declarations to an extent, even if you can share the implementation: static methods just can't be inherited, and interface methods (of which getMessage would be one) shall need an implementation everywhere. I mean this way of being "DRY" will have many ways of being inelegant.

If I were you, I would simply make this data completely dynamic

final class MenuOption {
    private final String category; //MAIN_MENU, HOT_SELECTION
    private final String message; //Exit, View Reservation By Host, etc.
    public static MenuOption of(String key, String message) {
        return new MenuOption(key, message);
    }
}

This is very scalable, although it introduces the need to validate data where enums would statically prevent bad options, and possibly custom code where an enum would offer built-in support.

It can be improved with a "category" enum, which gives static access to menu lists, and a single place for asListString():

enum MenuCategory {
    MAIN_MENU(
        MenuOption.of("Exit"), 
        MenuOption.of("View Reservations By Host")
    ),
    HOT_SELECTION(
        MenuOption.of("Find All")
    );
    
    private final List<MenuOption> menuOptions;
    
    MenuCategory(MenuOption... options) {
        this.menuOptions = List.of(options); //unmodifiable
    }
    
    public List<String>asListString() {
        return this.menuOptions.stream()
                   .map(MenuOption::getMessage)
                   .collect(Collectors.toList());
    }
}

It should be clear that you can replace class MenuOption with a bunch of enums implementing a common interface, which should change little to nothing in MenuCategory. I wouldn't do that, but it's an option.

I basically had the same idea as davidalayachew.

An enum can implement an interface. So if you create a common asListString which accepts an enum type, you could get the desired result.

First, create an Options interface and let both enums implement it:

interface Options {
    String getMessage();
}

enum HostSelectionMethodOptions implements Options { ... }
enum MainMenuOptions implements Options { ... }

Now create a method like this:

public static <T extends Enum<T> & Options> List<String> asListString(Class<T> type) {
    return Arrays.stream(type.getEnumConstants())
        .map(T::getMessage)
        .collect(Collectors.toList());
}

The method declares a type argument: <T extends Enum<T> & Options>. Here, T is an intersection type, so it extends both Enum and the Options interface. You can call it like this:

asListString(MainMenuOptions.class);

You can DRY it a little.

Utils.java

import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

public interface Utils<T>
{

   public String getMessage();

   public static <T extends Utils<T>> List<String> asListString(Class<T> clazz)
   {
   
      return Arrays.stream(clazz.getEnumConstants())
                .map(T::getMessage)
                .collect(Collectors.toList());
   
   }
   
}

HostSelectionMethodOptions.java

public enum HostSelectionMethodOptions implements Utils<HostSelectionMethodOptions> {
   
   FIND_ALL("Find all"),
   FIND_BY_LASTNAME_PREFIX("Find by last name prefix"),
   FIND_BY_CITY_STATE("Find by city & state");
   
   private final String message;
   
   HostSelectionMethodOptions(String message) {
      this.message = message;
   }
   
   public String getMessage() {
      return message;
   }
   
}

Then just do this - Utils.asListString(HostSelectionMethodOptions.class);