public boolean get(long index) {
    int i = (int) (index >> 6);               // div 64
    int bit = (int) index & 0x3f;           // mod 64
    long bitmask = 1L << bit;
    // TODO perfectionist one can implement this using bit operations
    return (bits[i / PAGE_SIZE][i % PAGE_SIZE] & bitmask) != 0;
  }
Returns true or false for the specified bit index.
The index should be less than the OpenBitSet size.
ambry-utils/src/main/java/com/github/ambry/utils/OpenBitSet.java