Enum based and memory efficient flag set.

BitSet.java

public class BitSet<T extends Enum<?>> {

	private byte[] bytes;

	@SafeVarargs
	public BitSet(T... elements) {
		bytes = new byte[elements.length / 8 + 1];
	}

	private int bitMask(int ordinal) {
		return 1 << (ordinal % 8);
	}

	public boolean get(T flag) {
		return (bytes[flag.ordinal() / 8] & bitMask(flag.ordinal())) != 0;
	}

	public void set(T flag, boolean value) {
		if (value)
			bytes[flag.ordinal() / 8] |= bitMask(flag.ordinal());
		else
			bytes[flag.ordinal() / 8] &= ~bitMask(flag.ordinal());
	}

	@Override
	public String toString() {
		StringBuffer sb = new StringBuffer();
		sb.append("[");
		for (int i = bytes.length - 1; i >= 0; i--) {
			for (int j = 7; j >= 0; j--) {
				sb.append((bytes[i] & bitMask(j)) != 0 ? 1 : 0);
			}
		}
		sb.append("]");
		return sb.toString();
	}

	private static enum Caracteristics {
		IsBig, IsHeavy, IsHuman, IsDangerous, IsBeautiful, IsVisible, IsSolid, IsSmart, IsNatural;
	}

	public static void main(String[] args) {
		BitSet<Caracteristics> bs = new BitSet<>(Caracteristics.values());
		bs.set(Caracteristics.IsBig, true);
		bs.set(Caracteristics.IsHeavy, false);
		bs.set(Caracteristics.IsDangerous, true);
		bs.set(Caracteristics.IsSmart, true);
		bs.set(Caracteristics.IsNatural, true);

		System.out.println(bs.get(Caracteristics.IsBig));
		System.out.println(bs.get(Caracteristics.IsHeavy));
		System.out.println(bs.get(Caracteristics.IsDangerous));
		System.out.println(bs.get(Caracteristics.IsSmart));
		System.out.println(bs.get(Caracteristics.IsNatural));
		System.out.println(bs);
	}

}