Miscellaneous Utilities - The Java Programming Language - page 939

public void flip(int index)
Sets the bit specified by index to the complement of its current
value true becomes false , and false becomes true .
public boolean get(int index)
Returns the value of the bit specified by index .
A second overloaded form of each of the above methods works on a
range of bits. These overloads take a from index and a to index and
either sets, clears, flips, or returns all bits in the range, starting with
from and up to but not including to . For get , the values are returned as a
new BitSet . A third overload of clear takes no arguments and clears the
entire set to false . A second variant of the set method takes both the
index (or range) and a boolean value to apply to the bits. This makes
it easier for you to change bits arbitrarily without having to work out
whether you need to invoke set or clear .
You can find the index of the next clear or set bit, that is at or after a
given index, using the nextClearBit and nextSetBit methods. If there is
no next set bit from that index then 1 is returned. [1]
[1] The only time there can be no next clear bit is if the bit at index Integer.MAX_VALUE has been
setsomething that is extremely unlikely in practice because the bit set could use a huge amount of
memory
Other methods modify the current bit set by applying bitwise logical op-
erations using the bits from another bit set:
public void and(BitSet other)
Logically AND s this bit set with other and changes the value of
this set to the result. The resulting value of a bit in this bit set
is TRue only if it was originally true and the corresponding bit
in other is also true .