question: public static void random ( byte [ ] b , int offset , int length ) { checkPositionIndex ( offset , b . length , "offset" ) ; checkArgument ( length > 0 , "length must be greater than 0" ) ; checkPositionIndex ( offset + length , b . length , "offset + length" ) ; byte [ ] buf = new byte [ length ] ; RNG . nextBytes ( buf ) ; System . arraycopy ( buf , 0 , b , offset , length ) ; }
target:  Fill given array with random bytes at the specified position.