question: public long [ ] [ ] initializeHashFunctions ( ) { int numberOfHashFunctions ; int bigPrimeInt = ( int ) bigPrime ; numberOfHashFunctions = ( int ) Math . floor ( Math . log ( 2 ) * bitSet . length ( ) / expectedNumberOfObjects ) ; if ( numberOfHashFunctions == 0 ) numberOfHashFunctions = 1 ; long [ ] [ ] hashFunctions = new long [ numberOfHashFunctions ] [ 2 ] ; for ( long [ ] h : hashFunctions ) { h [ 0 ] = ( long ) RANDOM . nextInt ( bigPrimeInt ) + 1 ; h [ 1 ] = ( long ) RANDOM . nextInt ( bigPrimeInt ) + 1 ; } return hashFunctions ; }
target:  Builds an array of pairs of long that can be used as hash functions for this Bloom filter.