question: public static double round ( double number , int decimalPlace ) { double multiplier = Math . pow ( 10 , decimalPlace ) ; return Math . round ( number * multiplier ) / multiplier ; }
target:  Well, this is the fastest (I think) method with little bit compromise on accuracy in some cases. There exists some other methods using BigDecimal, deciamlFormats, which I think, for me not so necessary. 