停止Java枚举中的重复

public enum Color {
    RED, GREEN, BLUE, RED, YELLOW, GREEN;

    public static List<Color> getUniqueValues() {
        Set<Color> set = new HashSet<>();
        for (Color color : values()) {
            set.add(color);
        }
        return new ArrayList<>(set);
    }
}

public class Main {
    public static void main(String[] args) {
        List<Color> uniqueValues = Color.getUniqueValues();
        for (Color color : uniqueValues) {
            System.out.println(color);
        }
    }
}

RED
GREEN
BLUE
YELLOW