Every DecimalFormat object has a pattern that describes how numbers are formatted and a list of symbols that describes with which characters they’re formatted. This allows the single DecimalFormat class to be parameterized so that it can handle many different formats for different kinds of numbers in many locales. The pattern is given as an ASCII string. The symbols are provided by a DecimalFormatSymbols object. These are accessed and manipulated through the following six methods:

public DecimalFormatSymbols getDecimalFormatSymbols()
public void setDecimalFormatSymbols(DecimalFormatSymbols newSymbols)
public String toPattern()
public String toLocalizedPattern()
public void applyPattern(String pattern)
public void applyLocalizedPattern(String pattern)

The decimal format symbols specify the characters or strings used for the zero digit, the grouping separator, the decimal sign, the percent sign, the mille percent sign, infinity (IEEE 754 Inf), not a number (IEEE 754 NaN), and the minus sign. In American English these are 0, ,, ., %, ‰, Inf, NaN, and -, respectively. They may be other things in different locales.

The pattern specifies whether leading and trailing zeros are to be printed, whether the fractional part of the number is printed, the number of digits in a group (three in American English), and the leading and trailing suffixes for negative and positive numbers. Patterns are described using an almost Backus-Naur Form (BNF) grammar, given here:

pattern     ->  subpattern{;subpattern}
subpattern  ->  {prefix}integer{.fraction}{suffix}
prefix      ->  '\u0000'..'\uFFFD' - specialCharacters
suffix      ->  '\u0000'..'\uFFFD' - specialCharacters
integer     ->  '#'* '0'* '0'
fraction    ->  '0'* '#'*

The first line is not pure BNF. The first subpattern is used for positive numbers. The second subpattern, which may not be present, is used for negative numbers. If it’s not present, negative numbers use the positive format but are prefixed with a minus sign. Table 16.2 defines the symbols used in the grammar.

,

;

-

%

X

'

X*

(X | Y)

X..Y

S - T

This results in patterns like those seen in Table 16.3 for various locales. For instance, #,##0.### is the decimal format pattern for U.S. English and most other non-Arabic-speaking locales. The # mark means any digit character except a leading or trailing zero. The comma is the grouping separator, the period is the decimal point separator, and the is a digit that will be printed even if it’s a nonsignificant zero. You interpret this pattern as follows:

It’s relatively painful to work with this grammar directly. Fortunately, there are methods that allow you to get and set the values of these individual pieces directly, and I recommend that you use them:

public String getPositivePrefix()
public void setPositivePrefix(String newValue)
public String getPositiveSuffix()
public void setPositiveSuffix(String newValue)
public String getNegativePrefix()
public void setNegativePrefix(String newValue)
public String getNegativeSuffix()
public void setNegativeSuffix(String newValue)
public int getMultiplier()
public void setMultiplier(int newValue)
public int getGroupingSize()
public void setGroupingSize(int newValue)
public boolean isDecimalSeparatorAlwaysShown()
public void setDecimalSeparatorAlwaysShown(boolean newValue)

I can only guess why the patterns and the decimal format symbols themselves are exposed as much as they are in the java.text package. In my opinion, this is poor design, since it ties the interface too closely to the implementation of the class. The get and set methods are fully adequate for manipulating the formatting. Since you probably won’t be setting a pattern more than once or twice in a program (how many different formats does one program need?), there’s no significant performance gain by using a pattern instead of the get and set methods. And there is a significant cost in complexity. Allowing direct setting of patterns requires the class to check that the patterns are valid and throw a ParseException if they’re not. The only advantage I can see to manipulating number formats as pattern strings is that it makes them easy to store in resource bundles. However, I’m not sure this ability really needs to be public.

The positive prefix is the string prefixed to positive numbers. Most of the time this is the empty string “”, but in some circumstances you might want to use a plus sign (+). In currency formats, the positive prefix is often set to the currency sign, like $ or £, depending on the locale. You can also set a positive suffix; that is, a string that is appended to all positive numbers. I’m not aware of any number formats that use positive suffixes, but if you need to, you can. The negative prefix is the minus sign (-). However, in accounting and other financial applications it may be an open parenthesis instead. In these applications, there’s also a negative suffix, generally a closing parenthesis. Thus, -12 might be formatted as (12).

The multiplier is an integer by which the number is multiplied before being formatted. This is commonly used in percent formats. This allows a number like 0.85 to be formatted as 85% instead of 0.85%. 1, 100, and 1000 are the only common values of this number. Grouping size is the number of digits between grouping separators, commas in English. This is how 75365 becomes 75,365. Most locales, including English, break every three digits; a few break every four, formatting 75365 as 7,5365. Finally, you can specify whether or not the decimal separator (decimal point) is shown in numbers without fractional parts. By default, a number like 1999 does not have a decimal point. However, there are situations (C source code, for example) where the difference between 1999 and 1999. is significant.

You also have access to the following methods, inherited from java.text.NumberFormat, which allow you to set and get the minimum and maximum number of integer and fraction digits and control whether or not grouping is used at all. These work just as well with decimal formats as they do with regular number formats.

public boolean isGroupingUsed()
public void setGroupingUsed(boolean useGrouping)
public int getMaximumIntegerDigits()
public void setMaximumIntegerDigits(int maxDigits)
public int getMinimumIntegerDigits()
public void setMinimumIntegerDigits(int minDigits)
public int getMaximumFractionDigits()
public void setMaximumFractionDigits(int maxDigits)
public int getMinimumFractionDigits()
public void setMinimumFractionDigits(int minDigits)

Table 16.3 lists the default patterns used by different locales’ decimal formats. For the basic decimal format shown in columns 2 and 3, most of the locales use the same pattern as the U.S. English locale. The notable exceptions are the Arabic-speaking countries and Macedonia. The primary difference between locales comes in the decimal format symbols, not the pattern. The percent formats, (not shown) all round down to the nearest integer. With one exception, all locales share the percent format #,##0%. The one exception is the #,##0‰ used in the mainland China locale. This uses a per mille (per thousand), as opposed to the more common percent (per hundred).

The currency formats, shown in columns 4 and 5, are a lot more interesting, because most countries have their own currencies with their own unique symbols. Even when countries share a symbol and a name for the currency, such as the dollar ($), it’s still important to distinguish between Canadian, American, and Australian dollars. Many of the currencies in Table 16.3, especially for country-independent language locales, use the ¤ symbol, which refers to a currency of indeterminate type. The [RLM] you’ll see in many of the Arabic formats stands for the non-printing Unicode character u200f, the right-to-left marker, used to ensure proper directionality in the number in Arabic’s right-to-left system. Hebrew is also a right-to-left script, but in modern Hebrew numbers are generally written in the European fashion from left to right.

Table 16-3. Decimal Format Patterns

Language (Country)	Decimal Pattern	Example:-1234.56	Currency Pattern	Example: -1,234.56
Albanian	#,##0.###	-1.234,56	¤ #,##0.00	-¤ 1.234,56
Albanian (Albania)	#,##0.###	-1.234,56	Lek#,##0.###	-Lek1.234,56
Arabic	#,##0.###	-1,234.56	¤ #,##0.00	-¤ 1,234.56
Arabic (Algeria)	#,##0.###; #, ##0.###-	1,234.56-	.[RLM] #,##0.###; [RLM] #,##0.###-	[RLM] 1,234.56-
Arabic (Bahrain)	#,##0.###;#, ##0.###-	1,234.56-	[RLM] #,##0.###; [RLM] #,##0.###-	[RLM] 1,234.56-
Arabic (Egypt)	#,##0.###;#, ##0.###-	1,234.56-	[RLM] #,##0.###; [RLM] #,##0.###-	[RLM] 1,234.56-
Arabic (Iraq)	#,##0.###;#, ##0.###-	1,234.56-	[RLM] #,##0.###; [RLM] #,##0.###-	[RLM] 1,234.56-
Arabic (Jordan)	#,##0.###;#, ##0.###-	1,234.56-	[RLM] #,##0.###; [RLM] #,##0.###-	[RLM] 1,234.56-
Arabic (Kuwait)	#,##0.###;#, ##0.###-	1,234.56-	[RLM] #,##0.###; [RLM] #,##0.###-	[RLM] 1,234.56-
Arabic (Lebanon)	#,##0.###;#, ##0.###-	1,234.56-	[RLM] #,##0.###; [RLM] #,##0.###-	[RLM] 1,234.56-
Arabic (Libyan Arab Jamahiriya)	#,##0.###;#, ##0.###-	1,234.56-	[RLM] #,##0.###; [RLM] #,##0.###-	[RLM] 1,234.56-
Arabic (Morocco)	#,##0.###;#, ##0.###-	1,234.56-	[RLM] #,##0.###; [RLM] #,##0.###-	[RLM] 1,234.56-
Arabic (Oman)	#,##0.###;#, ##0.###-	1,234.56-	[RLM] #,##0.###; [RLM] #,##0.###-	[RLM] 1,234.56-
Arabic (Qatar)	#,##0.###; #,##0.###-	1,234.56-	[RLM] #,##0.###; [RLM] #,##0.###-	[RLM] 1,234.56-
Arabic (Saudi Arabia)	#,##0.###; #,##0.###-	1,234.56-	[RLM] #,##0.###; [RLM] #,##0.###-	[RLM] 1,234.56-
Arabic (Sudan)	#,##0.###; #,##0.###-	1,234.56-	[RLM] #,##0.###; [RLM] #,##0.###-	[RLM] 1,234.56-
Arabic (Syria)	#,##0.###; #,##0.###-	1,234.56-	[RLM] #,##0.###; [RLM] #,##0.###-	[RLM] 1,234.56-
Arabic (Tunisia)	#,##0.###; #,##0.###-	1,234.56-	[RLM] #,##0.###; [RLM] #,##0.###-	[RLM] 1,234.56-
Arabic (United Arab Emirates)	#,##0.###; #,##0.###-	1,234.56-	[RLM] #,##0.###; [RLM] #,##0.###-	[RLM] 1,234.56-
Arabic (Yemen)	#,##0.###; #,##0.###-	1,234.56-	[RLM] #,##0.###; [RLM] #,##0.###-	[RLM] 1,234.56-
Bulgarian	#,##0.###	-1 234,56	¤ #,##0.00	-¤ 1 234,56
Bulgarian (Bulgaria)	#,##0.###	-1 234,56	#,##0.##	- 1 234,56
Byelorussian	#,##0.###	-1 234,56	¤ #,##0.00	-¤ 1 234,56
Byelorussian (Belarus)	#,##0.###	-1 234,56	#,##0.##	- 1 234,56
Catalan	#,##0.###	-1.234,56	¤ #,##0.00	-¤ 1.234,56
Catalan (Spain)	#,##0.###	-1.234,56	Pts #,##0	-Pts 1.235
Chinese	#,##0.###	-1,234.56	¤ #,##0.00	-¤ 1,234.56
Chinese (China)	#,##0.###	-1,234.56	¥#,##0.00	-¥1,234.56
Chinese (Taiwan)	#,##0.###	-1,234.56	NT$#,##0.00	-NT$1,234.56
Croatian	#,##0.###	-1.234,56	¤ #,##0.00	-¤ 1.234,56
Croatian (Croatia)	#,##0.###	-1.234,56	Kn #,##0.##	-Kn 1.234,56
Czech	#,##0.###	-1.234,56	¤ #,##0.00	-¤ 1.234,56
Czech (Czech Republic)	#,##0.###	-1.234,56	#,##0.##; -#,##0.##	-1.234,56
Danish	#,##0.###	-1.234,56	¤ #,##0.00	-¤ 1.234,56
Danish (Denmark)	#,##0.###	-1.234,56	kr #,##0.00; kr -#,##0.00	kr -1.234,56
Dutch	#,##0.###	-1.234,56	¤ #,##0.00	-¤ 1.234,56
Dutch (Belgium)	#,##0.###	-1.234,56	#,##0.00 BF	-1.234,56 BF
Dutch (Netherlands)	#,##0.###	-1.234,56	fl #,##0.00; fl #,##0.00-	fl 1.234,56-
English	#,##0.###	-1,234.56	¤ #,##0.00	-¤ 1,234.56
English (Australia)	#,##0.###	-1,234.56	$#,##0.00	-$1,234.56
English (Canada)	#,##0.###	-1,234.56	$#,##0.00	-$1,234.56
English (Ireland)	#,##0.###	-1,234.56	IR£#,##0.00	-IR£1,234.56
English (New Zealand)	#,##0.###	-1,234.56	$#,##0.00	-$1,234.56
English (South Africa)	#,##0.###	-1,234.56	R #,##0.00; R-#,##0.00	R-1,234.56
English (United Kingdom)	#,##0.###	-1,234.56	£#,##0.00	-£1,234.56
English (United States)	#,##0.###	-1,234.56	$#,##0.00; ($#,##0.00)	($1,234.56)
Estonian	#,##0.###	-1 234,56	¤ #,##0.00	-¤ 1 234,56
Estonian (Estonia)	#,##0.###	-1 234,56	#,##0.## kr	-1 234,56 kr
Finnish	#,##0.###	-1 234,56	¤ #,##0.00	-¤ 1 234,56
Finnish (Finland)	#,##0.###	-1 234,56	#,##0.00 mk	-1 234,56 mk
French	#,##0.###	-1,234,56	¤ #,##0.00	-¤ 1,234,56
French (Belgium)	#,##0.###	-1.234,56	#,##0.00 FB	-1.234,56 FB
French (Canada)	#,##0.###	-1 234,56	#,##0.00 $; (#,##0.00$)	(1 234,56$)
French (France)	#,##0.###	-1 234,56	#,##0.00 F	-1 234,56 F
French (Switzerland)	#,##0.###	-1’234.56	SFr. #,##0.00; SFr.-#,##0.00	SFr.-1’234.56
German	#,##0.###	-1.234,56	¤ #,##0.00	-¤ 1.234,56
German (Austria)	#,##0.###	-1.234,56	öS #,##0.00	- öS 1.234,56
German (Germany)	#,##0.###	-1.234,56	#,##0.00 DM	-1.234,56 DM
German (Switzerland)	#,##0.###	-1’234.56	SFr. #,##0.00; SFr.-#,##0.00	SFr.-1’234.56
Greek	#,##0.###	-1.234,56	¤ #,##0.00	-¤ 1.234,56
Greek (Greece)	#,##0.###	-1.234,56	#,##0.00	-1.234,56
Hebrew	#,##0.###	-1,234.56	¤ #,##0.00	-¤ 1,234.56
Hebrew (Israel)	#,##0.###	-1,234.56	#,##0.##	-1,234.56
Hungarian	#,##0.###	-1 234,56	¤ #,##0.00	-¤ 1 234,56
Hungarian (Hungary)	#,##0.###	-1 234,56	Ft#,##0.##	-Ft1 234,56
Icelandic	#,##0.###	-1.234,56	¤ #,##0.00	-¤ 1.234,56
Icelandic (Iceland)	#,##0.###	-1.234,56	#,##0.## kr.	-1.234,56 kr.
Italian	#,##0.###	-1.234,56	¤ #,##0.00	-¤ 1.234,56
Italian (Italy)	#,##0.###	-1.234,56	L. #,##0	-L. 1.235
Italian (Switzerland)	#,##0.###	-1’234.56	SFr. #,##0.00; SFr.-#,##0.00	SFr.-1’234.56
Japanese	#,##0.###	-1,234.56	¤ #,##0.00	-¤ 1,234.56
Japanese (Japan)	#,##0.###	-1,234.56	¥#,##0.00	-¥1,234.56
Korean	#,##0.###	-1,234.56	¤ #,##0.00	-¤ 1,234.56
Korean (South Korea)	#,##0.###	-1,234.56	#,##0	- 1,235
Latvian (Lettish)	#,##0.###	-1 234,56	¤ #,##0.00	-¤ 1 234,56
Latvian (Lettish) (Latvia)	#,##0.###	-1 234,56	#,##0.## Ls	-1 234,56 Ls
Lithuanian	#,##0.###	-1.234,56	¤ #,##0.00	-¤ 1.234,56
Lithuanian (Lithuania)	#,##0.##	-1.234,56	#,##0.## Lt	-1.234,56 Lt
Macedonian	#,##0.###	-1.234,56	¤ #,##0.00	-¤ 1.234,56
Macedonian (Macedonia)	#,##0.###; (#,##0.###)	(1.234,56)	Den #,##0.##	-Den 1.234,56
Norwegian	#,##0.###	-1 234,56	¤ #,##0.00	-¤ 1 234,56
Norwegian (Norway)	#,##0.###	-1 234,56	kr #,##0.00; kr -#,##0.00	kr -1 234,56
Norwegian (Norway)	#,##0.###	-1 234,56	kr #,##0.00; kr -#,##0.00	kr -1 234,56
Polish	#,##0.###	-1 234,56	¤ #,##0.00	-¤ 1 234,56
Polish (Poland)	#,##0.###	-1 234,56	#,##0.##	-1 234,56
Portuguese	#,##0.###	-1.234,56	¤ #,##0.00	-¤ 1.234,56
Portuguese (Brazil)	#,##0.###	-1.234,56	R$ #,##0.##	-R$ 1.234,56
Portuguese (Portugal)	#,##0.###	-1.234,56	#,##0.00 Esc.	-1.234,56 Esc.
Romanian	#,##0.###	-1.234,56	¤ #,##0.00	-¤ 1.234,56
Romanian (Romania)	#,##0.###	-1.234,56	#,##0.00 LEI	-1.234,56 LEI
Russian	#,##0.###	-1 234,56	¤ #,##0.00	-¤ 1 234,56
Russian (Russian Federation)	#,##0.###	-1 234,56	#,##0.##	-1 234,56
Serbian	#,##0.###	-1 234,56	¤ #,##0.00	-¤ 1 234,56
Serbian (Yugoslavia)	#,##0.###	-1 234,56	#,##0.00	- 1 234,56
Serbo-Croatian	#,##0.###	-1.234,56	¤ #,##0.00	-¤ 1.234,56
Serbo-Croatian (Yugoslavia)	#,##0.###	-1.234,56	Din #,##0.00	-Din 1.234,56
Slovak	#,##0.###	-1 234,56	¤ #,##0.00	-¤ 1 234,56
Slovak (Slovakia)	#,##0.###	-1 234,56	Sk #,##0.00 ; -#,##0.00 Sk	-1 234,56 Sk
Slovenian	#,##0.###	-1.234,56	¤ #,##0.00	-¤ 1.234,56
Slovenian (Slovenia)	#,##0.###	-1.234,56	tol #,##0.##	-tol 1.234,56
Spanish	#,##0.###	-1.234,56	¤ #,##0.00	-¤ 1.234,56
Spanish (Argentina)	#,##0.###	-1.234,56	$#,##0.00; ($#,##0.00)	($1.234,56)
Spanish (Bolivia)	#,##0.###	-1,234.56	B$#,##0.00; (B$#,##0.00)	(B$1,234.56)
Spanish (Chile)	#,##0.###	-1.234,56	Ch$#,##0.00; Ch$-#,##0.00	Ch$-1.234,56
Spanish (Colombia)	#,##0.###	-1,234.56	C$#,##0.00; (C$#,##0.00)	(C$1,234.56)
Spanish (Costa Rica)	#,##0.###	-1,234.56	C#,##0.00; (C#,##0.00)	(C1,234.56)
Spanish (Dominican Republic)	#,##0.###	-1,234.56	RD$#,##0.00; (RD$#,##0.00)	(RD$1,234.56)
Spanish (Ecuador)	#,##0.###	-1,234.56	S/#,##0.00; S/-#,##0.00	S/-1,234.56
Spanish (El Salvador)	#,##0.###	-1,234.56	C#,##0.00; (C#,##0.00)	(C1,234.56)
Spanish (Guatemala)	#,##0.###	-1,234.56	Q#,##0.00; (Q#,##0.00)	(Q1,234.56)
Spanish (Honduras)	#,##0.###	-1,234.56	L#,##0.00; (L#,##0.00)	(L1,234.56)
Spanish (Mexico)	#,##0.###	-1,234.56	$#,##0.00; ($#,##0.00)	($1,234.56)
Spanish (Nicaragua)	#,##0.###	-1,234.56	$C#,##0.00; ($C#,##0.00)	($C1,234.56)
Spanish (Panama)	#,##0.###	-1,234.56	B#,##0.00; (B#,##0.00)	(B1,234.56)
Spanish (Paraguay)	#,##0.###	-1.234,56	G#,##0.00; (G#,##0.00)	(G1.234,56)
Spanish (Peru)	#,##0.###	-1.234,56	S/#,##0.00; S/-#,##0.00	S/-1.234,56
Spanish (Puerto Rico)	#,##0.###	-1,234.56	$#,##0.00; ($#,##0.00)	($1,234.56)
Spanish (Spain)	#,##0.###	-1.234,56	#,##0.00 Pts	-1.234,56 Pts
Spanish (Uruguay)	#,##0.###	-1.234,56	NU$ #,##0.00; (NU$#,##0.00)	(NU$1.234,56)
Spanish (Venezuela)	#,##0.###	-1.234,56	Bs#,##0.00; Bs -#,##0.00	Bs -1.234,56
Swedish	#,##0.###	-1 234,56	¤ #,##0.00	-¤ 1 234,56
Swedish (Sweden)	#,##0.###	-1 234,56	#,##0.00 kr	-1 234,56 kr
Thai	#,##0.###	-1,234.56	¤ #,##0.00	-¤ 1,234.56
Thai (Thailand)	#,##0.###	-1,234.56	#,##0.00; -#,##0.00	-1,234.56
Turkish	#,##0.###	-1.234,56	¤ #,##0.00	-¤ 1.234,56
Turkish (Turkey)	#,##0.###	-1.234,56	#,##0.00 TL	-1.234,56 TL
Ukrainian	#,##0.###	-1.234,56	¤ #,##0.00	-¤ 1.234,56
Ukrainian (Ukraine)	#,##0.###	-1.234,56	#,##0.##	-1.234,56

Each DecimalFormat object has a DecimalFormatSymbols object that contains a list of the different symbols used by decimal number formats in a particular locale. The decimal format symbols specify the characters or strings used for the zero digit, the grouping separator, the decimal sign, the percent sign, the mille percent sign, infinity (IEEE 754 Inf), not a number (IEEE 754 NaN), and the minus sign. DecimalFormatSymbols has two constructors, but they’re rarely used:

public DecimalFormatSymbols()
public DecimalFormatSymbols(Locale locale)

Instead, the DecimalFormatSymbols object is retrieved from a particular DecimalFormat object using its getDecimalFormatSymbols() method:

public DecimalFormatSymbols getDecimalFormatSymbols()

If you create your own DecimalFormatSymbols object, perhaps for a locale Java doesn’t support, you can make a DecimalFormat use it by passing it to DecimalFormat’s setDecimalFormatSymbols() method:

public void setDecimalFormatSymbols(DecimalFormatSymbols newSymbols)

The DecimalFormatSymbols class contains mostly get and set methods for inspecting and setting the values of the different symbols:

public char getZeroDigit()
public void setZeroDigit(char zeroDigit)
public char getGroupingSeparator()
public void setGroupingSeparator(char groupingSeparator)
public char getDecimalSeparator()
public void setDecimalSeparator(char decimalSeparator)
public char getPercent()
public void setPercent(char percent)
public char getPerMill()
public void setPerMill(char perMill)
public String getInfinity()
public void setInfinity(String infinity)
public String getNaN()
public void setNaN(String NaN)
public char getMinusSign()
public void setMinusSign(char minusSign)

The zero digit is the character used for zero. This is in most Western languages but is different in Arabic and a few other locales. The grouping separator is the character used to split groups; a comma is used in the U.S., but a period is used in some other countries that use a comma as the decimal separator. The decimal separator is a decimal point (a period) in English but a comma in some other locales. The percent and per mille characters are % and ‰ in English, occasionally other things in other locales. The infinity and not-a-number strings are rarely changed. They’re Inf and NaN as specified by IEEE 754, generally even in non-English languages like German, where the word for infinity is Unbegrenztheit and “not a number” translates as “nicht eine Zahl.” Finally, the minus sign is the default character used for negative numbers that do not have a specific prefix. It’s a hyphen (-) in English. This character is not used if the associated pattern has set a negative prefix.

The DecimalFormatSymbols class also lets you set two of the characters used in patterns. The digit character, # by default, and the pattern separator character, a semicolon by default, can be changed if you want to use one of those characters as a literal in the pattern; for example, by using a # instead of a period for the decimal separator.

public char getDigit()
public void setDigit(char digit)
public char getPatternSeparator()
public void setPatternSeparator(char patternSeparator)

The pattern separator is used to separate positive from negative patterns. If no explicit negative pattern is given, then a minus sign is simply prefixed onto the positive pattern instead.

public int hashCode()
public boolean equals(Object obj)
public Object clone()

Most of the time, you use the factory methods in NumberFormat to get DecimalFormat instances. However, there are three public DecimalFormat constructors you can use to create DecimalFormat instances directly:

public DecimalFormat()
public DecimalFormat(String pattern)
public DecimalFormat(String pattern, DecimalFormatSymbols symbols)

The no-argument constructor creates a decimal format that uses the default pattern and symbols for the default locale. The second constructor creates a decimal format that uses the specified pattern and the default symbols for the default locale. The third constructor creates a decimal format that uses the specified pattern and the specified symbols for the default locale. These are useful for special cases that aren’t handled by the default patterns and symbols.