System.out.println("BitSet.of(1) == " + a);
a.add(2);
a.add(3);
a.add(4);
System.out.println("a == " + a);
System.out.println("a.clone() == " + a.clone());
BitSet b = BitSet.of(2);
System.out.println("b == " + b);
System.out.println("b.not() == " + b.not());
System.out.println("a.not() == " + a.not());
System.out.println("a.equals(b) == " + a.equals(b));