question: @ Override public StringBuffer format ( double number , StringBuffer result , FieldPosition fieldPosition ) { boolean tryFastPath = false ; if ( fieldPosition == DontCareFieldPosition . INSTANCE ) tryFastPath = true ; else { fieldPosition . setBeginIndex ( 0 ) ; fieldPosition . setEndIndex ( 0 ) ; } if ( tryFastPath ) { String tempResult = fastFormat ( number ) ; if ( tempResult != null ) { result . append ( tempResult ) ; return result ; } } return format ( number , result , fieldPosition . getFieldDelegate ( ) ) ; }
target:  Formats a double to produce a string.