Java Language java.util.BitSet class


Example

Since 1.7 there's a java.util.BitSet class that provides simple and user-friendly bit storage and manipulation interface:

final BitSet bitSet = new BitSet(8); // by default all bits are unset

IntStream.range(0, 8).filter(i -> i % 2 == 0).forEach(bitSet::set); // {0, 2, 4, 6}

bitSet.set(3); // {0, 2, 3, 4, 6}

bitSet.set(3, false); // {0, 2, 4, 6}

final boolean b = bitSet.get(3); // b = false

bitSet.flip(6); // {0, 2, 4}

bitSet.set(100); // {0, 2, 4, 100} - expands automatically

BitSet implements Clonable and Serializable, and under the hood all bit values are stored in long[] words field, that expands automatically.

It also supports whole-set logical operations and, or, xor, andNot:

bitSet.and(new BitSet(8));
bitSet.or(new BitSet(8));
bitSet.xor(new BitSet(8));
bitSet.andNot(new BitSet(8));