how to create methods for enums java code example

Example: enum with methods in java example

public enum Level {
    HIGH{
        @Override
        public String asLowerCase() {
            return HIGH.toString().toLowerCase();
        }
    },
    MEDIUM{
        @Override
        public String asLowerCase() {
            return MEDIUM.toString().toLowerCase();
        }
    },
    LOW{
        @Override
        public String asLowerCase() {
            return LOW.toString().toLowerCase();
        }
    };

    public abstract String asLowerCase();
}