如何从枚举中提取所有值并将其添加到列表<String>

Question

The title is pretty self-explanatory. Here's my code so far:

public List<String> getVoucherStatuses() {
        List<String> listOfStatuses = new ArrayList<String>();

        for (VoucherStatus status : VoucherStatus.values()) {
            listOfStatuses.add(status.name());
        }
        return listOfStatuses;
    }

and here is the Enum:

public enum VoucherStatus {
        GENERATED, INVALID, ISSUED, REDEEMED, EXPIRED
    }

I keep getting null reference expcetion. What am I doing wrong? Thanks

Answer 1

If you're calling this from within the static initialiser of the enum, it wont have finished initialising which may well give you an NPE.

One work around is to use a nested class for the static.