1. Formatting Output Slides by Dr. Heuring
In the current version of Java you may format your output using a couple of classes.
Classes are in java.text.* package.
DateFormat
DecimalFormat
MessageFormat
SimpleDateFormat

2. Formatting a Decimal
DecimalFormat f = new DecimalFormat("###,###.00");
double value1 = ,
value2=0.4, value3 = ;
System.out.println("Value1 = "+f.format(value1));
System.out.println("Value2 = "+f.format(value2));
System.out.println("Value3 = "+f.format(value3));
Output:
Value1 = 1,224.57
Value2 = .40
Value3 = -10,000.00

3. The DecimalFormat Symbols
0 – digit or 0 if no digit.
# -- digit or blank if absent
. – decimal separator
- -- minus sign
, -- Grouping Separator
E – separator for mantissa and exponent in scientific notation
; -- separates positive and negative subpatterns
% -- multiply by 100 and show as a percnetage

4. Another Example for Decimals
DecimalFormat f2 = new DecimalFormat( " ###,##0.00;-###,##0.00");
System.out.println("Value1 = "+f2.format(value1));
System.out.println("Value2 = "+f2.format(value2));
System.out.println("Value3 = "+f2.format(value3));
Output
Value1 = 1,224.57
Value2 = 0.40
Value3 = -10,000.00