public boolean get(int index) {
    int i = index >> 6;               // div 64
    // signed shift will keep a negative index and force an
    // array-index-out-of-bounds-exception, removing the need for an explicit check.
    int bit = 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