question: private void readObject ( ObjectInputStream stream ) throws IOException , ClassNotFoundException { ObjectInputStream . GetField fields = stream . readFields ( ) ; this . symbols = ( DecimalFormatSymbols ) fields . get ( "symbols" , null ) ; initNative ( "" ) ; ndf . setPositivePrefix ( ( String ) fields . get ( "positivePrefix" , "" ) ) ; ndf . setPositiveSuffix ( ( String ) fields . get ( "positiveSuffix" , "" ) ) ; ndf . setNegativePrefix ( ( String ) fields . get ( "negativePrefix" , "-" ) ) ; ndf . setNegativeSuffix ( ( String ) fields . get ( "negativeSuffix" , "" ) ) ; ndf . setMultiplier ( fields . get ( "multiplier" , 1 ) ) ; ndf . setGroupingSize ( fields . get ( "groupingSize" , ( byte ) 3 ) ) ; ndf . setGroupingUsed ( fields . get ( "groupingUsed" , true ) ) ; ndf . setDecimalSeparatorAlwaysShown ( fields . get ( "decimalSeparatorAlwaysShown" , false ) ) ; setRoundingMode ( ( RoundingMode ) fields . get ( "roundingMode" , RoundingMode . HALF_EVEN ) ) ; final int maximumIntegerDigits = fields . get ( "maximumIntegerDigits" , 309 ) ; final int minimumIntegerDigits = fields . get ( "minimumIntegerDigits" , 309 ) ; final int maximumFractionDigits = fields . get ( "maximumFractionDigits" , 340 ) ; final int minimumFractionDigits = fields . get ( "minimumFractionDigits" , 340 ) ; ndf . setMaximumIntegerDigits ( maximumIntegerDigits ) ; super . setMaximumIntegerDigits ( ndf . getMaximumIntegerDigits ( ) ) ; setMinimumIntegerDigits ( minimumIntegerDigits ) ; setMinimumFractionDigits ( minimumFractionDigits ) ; setMaximumFractionDigits ( maximumFractionDigits ) ; setParseBigDecimal ( fields . get ( "parseBigDecimal" , false ) ) ; if ( fields . get ( "serialVersionOnStream" , 0 ) < 3 ) { setMaximumIntegerDigits ( super . getMaximumIntegerDigits ( ) ) ; setMinimumIntegerDigits ( super . getMinimumIntegerDigits ( ) ) ; setMaximumFractionDigits ( super . getMaximumFractionDigits ( ) ) ; setMinimumFractionDigits ( super . getMinimumFractionDigits ( ) ) ; } }
target:  Reads serialized fields following serialized forms specified by Java specification.