Immutable, arbitraryprecision signed decimal numbers. A
BigDecimal
consists of an arbitrary precision integer
unscaled value and a 32bit integer scale. If zero
or positive, the scale is the number of digits to the right of the
decimal point. If negative, the unscaled value of the number is
multiplied by ten to the power of the negation of the scale. The
value of the number represented by the BigDecimal
is
therefore (unscaledValue × 10^{scale}).
The BigDecimal
class provides operations for
arithmetic, scale manipulation, rounding, comparison, hashing, and
format conversion. The toString()
method provides a
canonical representation of a BigDecimal
.
The BigDecimal
class gives its user complete control
over rounding behavior. If no rounding mode is specified and the
exact result cannot be represented, an exception is thrown;
otherwise, calculations can be carried out to a chosen precision
and rounding mode by supplying an appropriate MathContext
object to the operation. In either case, eight rounding
modes are provided for the control of rounding. Using the
integer fields in this class (such as ROUND_HALF_UP
) to
represent rounding mode is largely obsolete; the enumeration values
of the RoundingMode
enum
, (such as HALF_UP
) should be used instead.
When a MathContext
object is supplied with a precision
setting of 0 (for example, UNLIMITED
),
arithmetic operations are exact, as are the arithmetic methods
which take no MathContext
object. (This is the only
behavior that was supported in releases prior to 5.) As a
corollary of computing the exact result, the rounding mode setting
of a MathContext
object with a precision setting of 0 is
not used and thus irrelevant. In the case of divide, the exact
quotient could have an infinitely long decimal expansion; for
example, 1 divided by 3. If the quotient has a nonterminating
decimal expansion and the operation is specified to return an exact
result, an ArithmeticException
is thrown. Otherwise, the
exact result of the division is returned, as done for other
operations.
When the precision setting is not 0, the rules of
BigDecimal
arithmetic are broadly compatible with selected
modes of operation of the arithmetic defined in ANSI X3.2741996
and ANSI X3.2741996/AM 12000 (section 7.4). Unlike those
standards, BigDecimal
includes many rounding modes, which
were mandatory for division in BigDecimal
releases prior
to 5. Any conflicts between these ANSI standards and the
BigDecimal
specification are resolved in favor of
BigDecimal
.
Since the same numerical value can have different representations (with different scales), the rules of arithmetic and rounding must specify both the numerical result and the scale used in the result's representation.
In general the rounding modes and precision setting determine
how operations return results with a limited number of digits when
the exact result has more digits (perhaps infinitely many in the
case of division) than the number of digits returned.
First, the
total number of digits to return is specified by the
MathContext
's precision
setting; this determines
the result's precision. The digit count starts from the
leftmost nonzero digit of the exact result. The rounding mode
determines how any discarded trailing digits affect the returned
result.
For all arithmetic operators , the operation is carried out as though an exact intermediate result were first calculated and then rounded to the number of digits specified by the precision setting (if necessary), using the selected rounding mode. If the exact result is not returned, some digit positions of the exact result are discarded. When rounding increases the magnitude of the returned result, it is possible for a new digit position to be created by a carry propagating to a leading "9" digit. For example, rounding the value 999.9 to three digits rounding up would be numerically equal to one thousand, represented as 100×10^{1}. In such cases, the new "1" is the leading digit position of the returned result.
Besides a logical exact result, each arithmetic operation has a preferred scale for representing a result. The preferred scale for each operation is listed in the table below.
Operation  Preferred Scale of Result 

Add  max(addend.scale(), augend.scale()) 
Subtract  max(minuend.scale(), subtrahend.scale()) 
Multiply  multiplier.scale() + multiplicand.scale() 
Divide  dividend.scale()  divisor.scale() 
1/32
is 0.03125
.
Before rounding, the scale of the logical exact intermediate
result is the preferred scale for that operation. If the exact
numerical result cannot be represented in precision
digits, rounding selects the set of digits to return and the scale
of the result is reduced from the scale of the intermediate result
to the least scale which can represent the precision
digits actually returned. If the exact result can be represented
with at most precision
digits, the representation
of the result with the scale closest to the preferred scale is
returned. In particular, an exactly representable quotient may be
represented in fewer than precision
digits by removing
trailing zeros and decreasing the scale. For example, rounding to
three digits using the {@linkplain RoundingMode#FLOOR floor}
rounding mode,
19/100 = 0.19 // integer=19, scale=2
but
21/110 = 0.190 // integer=190, scale=3
Note that for add, subtract, and multiply, the reduction in scale will equal the number of digit positions of the exact result which are discarded. If the rounding causes a carry propagation to create a new highorder digit position, an additional digit of the result is discarded than when no new digit position is created.
Other methods may have slightly different rounding semantics.
For example, the result of the pow
method using the
{@linkplain #pow(int, MathContext) specified algorithm} can
occasionally differ from the rounded mathematical result by more
than one unit in the last place, one {@linkplain #ulp() ulp}.
Two types of operations are provided for manipulating the scale
of a BigDecimal
: scaling/rounding operations and decimal
point motion operations. Scaling/rounding operations (setScale
and round
) return a
BigDecimal
whose value is approximately (or exactly) equal
to that of the operand, but whose scale or precision is the
specified value; that is, they increase or decrease the precision
of the stored number with minimal effect on its value. Decimal
point motion operations (movePointLeft
and
movePointRight
) return a
BigDecimal
created from the operand by moving the decimal
point a specified distance in the specified direction.
For the sake of brevity and clarity, pseudocode is used
throughout the descriptions of BigDecimal
methods. The
pseudocode expression (i + j)
is shorthand for "a
BigDecimal
whose value is that of the BigDecimal
i
added to that of the BigDecimal
j
." The pseudocode expression (i == j)
is
shorthand for "true
if and only if the
BigDecimal
i
represents the same value as the
BigDecimal
j
." Other pseudocode expressions
are interpreted similarly. Square brackets are used to represent
the particular BigInteger
and scale pair defining a
BigDecimal
value; for example [19, 2] is the
BigDecimal
numerically equal to 0.19 having a scale of 2.
Note: care should be exercised if BigDecimal
objects
are used as keys in a SortedMap
or
elements in a SortedSet
since
BigDecimal
's natural ordering is inconsistent
with equals. See Comparable
, SortedMap
or SortedSet
for more
information.
All methods and constructors for this class throw
NullPointerException
when passed a null
object
reference for any input parameter.
Constant Summary
int  ROUND_CEILING  Rounding mode to round towards positive infinity. 
int  ROUND_DOWN  Rounding mode to round towards zero. 
int  ROUND_FLOOR  Rounding mode to round towards negative infinity. 
int  ROUND_HALF_DOWN  Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round down. 
int  ROUND_HALF_EVEN  Rounding mode to round towards the "nearest neighbor" unless both neighbors are equidistant, in which case, round towards the even neighbor. 
int  ROUND_HALF_UP  Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round up. 
int  ROUND_UNNECESSARY  Rounding mode to assert that the requested operation has an exact result, hence no rounding is necessary. 
int  ROUND_UP  Rounding mode to round away from zero. 
Field Summary
public static final BigDecimal  ONE  The value 1, with a scale of 0. 
public static final BigDecimal  TEN  The value 10, with a scale of 0. 
public static final BigDecimal  ZERO  The value 0, with a scale of 0. 
Public Constructor Summary
BigDecimal(char[] in, int offset, int len)
Translates a character array representation of a
BigDecimal into a BigDecimal , accepting the
same sequence of characters as the BigDecimal(String)
constructor, while allowing a subarray to be specified. 

BigDecimal(char[] in, int offset, int len, MathContext mc)
Translates a character array representation of a
BigDecimal into a BigDecimal , accepting the
same sequence of characters as the BigDecimal(String)
constructor, while allowing a subarray to be specified and
with rounding according to the context settings. 

BigDecimal(char[] in)
Translates a character array representation of a
BigDecimal into a BigDecimal , accepting the
same sequence of characters as the BigDecimal(String)
constructor. 

BigDecimal(char[] in, MathContext mc)
Translates a character array representation of a
BigDecimal into a BigDecimal , accepting the
same sequence of characters as the BigDecimal(String)
constructor and with rounding according to the context
settings. 

BigDecimal(String val, MathContext mc)
Translates the string representation of a
BigDecimal
into a BigDecimal , accepting the same strings as the
BigDecimal(String) constructor, with rounding
according to the context settings. 

BigDecimal(double val)
Translates a
double into a BigDecimal which
is the exact decimal representation of the double 's
binary floatingpoint value. 

BigDecimal(double val, MathContext mc)
Translates a
double into a BigDecimal , with
rounding according to the context settings. 

BigDecimal(BigInteger val, MathContext mc)
Translates a
BigInteger into a BigDecimal
rounding according to the context settings. 

BigDecimal(BigInteger unscaledVal, int scale)
Translates a
BigInteger unscaled value and an
int scale into a BigDecimal . 

BigDecimal(BigInteger unscaledVal, int scale, MathContext mc)
Translates a
BigInteger unscaled value and an
int scale into a BigDecimal , with rounding
according to the context settings. 

BigDecimal(int val)
Translates an
int into a BigDecimal . 

BigDecimal(int val, MathContext mc)
Translates an
int into a BigDecimal , with
rounding according to the context settings. 

BigDecimal(long val)
Translates a
long into a BigDecimal . 

BigDecimal(long val, MathContext mc)
Translates a
long into a BigDecimal , with
rounding according to the context settings. 
Public Method Summary
BigDecimal 
abs(MathContext mc)
Returns a
BigDecimal whose value is the absolute value
of this BigDecimal , with rounding according to the
context settings. 
BigDecimal 
abs()
Returns a
BigDecimal whose value is the absolute value
of this BigDecimal , and whose scale is
this.scale() . 
BigDecimal 
add(BigDecimal augend)
Returns a
BigDecimal whose value is (this +
augend) , and whose scale is max(this.scale(),
augend.scale()) . 
BigDecimal 
add(BigDecimal augend, MathContext mc)
Returns a
BigDecimal whose value is (this + augend) ,
with rounding according to the context settings. 
byte 
byteValueExact()
Converts this
BigDecimal to a byte , checking
for lost information. 
int  
BigDecimal 
divide(BigDecimal divisor, int scale, int roundingMode)
Returns a
BigDecimal whose value is (this /
divisor) , and whose scale is as specified. 
BigDecimal 
divide(BigDecimal divisor, int scale, RoundingMode roundingMode)
Returns a
BigDecimal whose value is (this /
divisor) , and whose scale is as specified. 
BigDecimal 
divide(BigDecimal divisor, int roundingMode)
Returns a
BigDecimal whose value is (this /
divisor) , and whose scale is this.scale() . 
BigDecimal 
divide(BigDecimal divisor, MathContext mc)
Returns a
BigDecimal whose value is (this /
divisor) , with rounding according to the context settings. 
BigDecimal 
divide(BigDecimal divisor, RoundingMode roundingMode)
Returns a
BigDecimal whose value is (this /
divisor) , and whose scale is this.scale() . 
BigDecimal 
divide(BigDecimal divisor)
Returns a
BigDecimal whose value is (this /
divisor) , and whose preferred scale is (this.scale() 
divisor.scale()) ; if the exact quotient cannot be
represented (because it has a nonterminating decimal
expansion) an ArithmeticException is thrown. 
BigDecimal[] 
divideAndRemainder(BigDecimal divisor, MathContext mc)
Returns a twoelement
BigDecimal array containing the
result of divideToIntegralValue followed by the result of
remainder on the two operands calculated with rounding
according to the context settings. 
BigDecimal[] 
divideAndRemainder(BigDecimal divisor)
Returns a twoelement
BigDecimal array containing the
result of divideToIntegralValue followed by the result of
remainder on the two operands. 
BigDecimal 
divideToIntegralValue(BigDecimal divisor, MathContext mc)
Returns a
BigDecimal whose value is the integer part
of (this / divisor) . 
BigDecimal 
divideToIntegralValue(BigDecimal divisor)
Returns a
BigDecimal whose value is the integer part
of the quotient (this / divisor) rounded down. 
double 
doubleValue()
Converts this
BigDecimal to a double . 
boolean  
float 
floatValue()
Converts this
BigDecimal to a float . 
int 
hashCode()
Returns the hash code for this
BigDecimal . 
int 
intValue()
Converts this
BigDecimal to an int . 
int 
intValueExact()
Converts this
BigDecimal to an int , checking
for lost information. 
long 
longValue()
Converts this
BigDecimal to a long . 
long 
longValueExact()
Converts this
BigDecimal to a long , checking
for lost information. 
BigDecimal  
BigDecimal  
BigDecimal 
movePointLeft(int n)
Returns a
BigDecimal which is equivalent to this one
with the decimal point moved n places to the left. 
BigDecimal 
movePointRight(int n)
Returns a
BigDecimal which is equivalent to this one
with the decimal point moved n places to the right. 
BigDecimal 
multiply(BigDecimal multiplicand, MathContext mc)
Returns a
BigDecimal whose value is (this ×
multiplicand), with rounding according to the context settings. 
BigDecimal 
multiply(BigDecimal multiplicand)
Returns a
BigDecimal whose value is (this ×
multiplicand), and whose scale is (this.scale() +
multiplicand.scale()) . 
BigDecimal 
negate()
Returns a
BigDecimal whose value is (this) ,
and whose scale is this.scale() . 
BigDecimal 
negate(MathContext mc)
Returns a
BigDecimal whose value is (this) ,
with rounding according to the context settings. 
BigDecimal 
plus()
Returns a
BigDecimal whose value is (+this) , and whose
scale is this.scale() . 
BigDecimal 
plus(MathContext mc)
Returns a
BigDecimal whose value is (+this) ,
with rounding according to the context settings. 
BigDecimal  
BigDecimal 
pow(int n)
Returns a
BigDecimal whose value is
(this^{n}), The power is computed exactly, to
unlimited precision. 
int 
precision()
Returns the precision of this
BigDecimal . 
BigDecimal  
BigDecimal 
remainder(BigDecimal divisor, MathContext mc)
Returns a
BigDecimal whose value is (this %
divisor) , with rounding according to the context settings. 
BigDecimal  
int 
scale()
Returns the scale of this
BigDecimal . 
BigDecimal 
scaleByPowerOfTen(int n)
Returns a BigDecimal whose numerical value is equal to
(
this * 10^{n}). 
BigDecimal 
setScale(int newScale, int roundingMode)
Returns a
BigDecimal whose scale is the specified
value, and whose unscaled value is determined by multiplying or
dividing this BigDecimal 's unscaled value by the
appropriate power of ten to maintain its overall value. 
BigDecimal 
setScale(int newScale)
Returns a
BigDecimal whose scale is the specified
value, and whose value is numerically equal to this
BigDecimal 's. 
BigDecimal 
setScale(int newScale, RoundingMode roundingMode)
Returns a
BigDecimal whose scale is the specified
value, and whose unscaled value is determined by multiplying or
dividing this BigDecimal 's unscaled value by the
appropriate power of ten to maintain its overall value. 
short 
shortValueExact()
Converts this
BigDecimal to a short , checking
for lost information. 
int 
signum()
Returns the signum function of this
BigDecimal . 
BigDecimal 
stripTrailingZeros()
Returns a
BigDecimal which is numerically equal to
this one but with any trailing zeros removed from the
representation. 
BigDecimal 
subtract(BigDecimal subtrahend)
Returns a
BigDecimal whose value is (this 
subtrahend) , and whose scale is max(this.scale(),
subtrahend.scale()) . 
BigDecimal 
subtract(BigDecimal subtrahend, MathContext mc)
Returns a
BigDecimal whose value is (this  subtrahend) ,
with rounding according to the context settings. 
BigInteger 
toBigInteger()
Converts this
BigDecimal to a BigInteger . 
BigInteger 
toBigIntegerExact()
Converts this
BigDecimal to a BigInteger ,
checking for lost information. 
String 
toEngineeringString()
Returns a string representation of this
BigDecimal ,
using engineering notation if an exponent is needed. 
String 
toPlainString()
Returns a string representation of this
BigDecimal
without an exponent field. 
String 
toString()
Returns the string representation of this
BigDecimal ,
using scientific notation if an exponent is needed. 
BigDecimal 
ulp()
Returns the size of an ulp, a unit in the last place, of this
BigDecimal . 
BigInteger 
unscaledValue()
Returns a
BigInteger whose value is the unscaled
value of this BigDecimal . 
static BigDecimal 
valueOf(double val)
Translates a
double into a BigDecimal , using
the double 's canonical string representation provided
by the toString(double) method. 
static BigDecimal 
valueOf(long val)
Translates a
long value into a BigDecimal
with a scale of zero. 
static BigDecimal 
valueOf(long unscaledVal, int scale)
Translates a
long unscaled value and an
int scale into a BigDecimal . 
Inherited Method Summary
Constants
public static final int ROUND_CEILING
Rounding mode to round towards positive infinity. If the
BigDecimal
is positive, behaves as for
ROUND_UP
; if negative, behaves as for
ROUND_DOWN
. Note that this rounding mode never
decreases the calculated value.
public static final int ROUND_DOWN
Rounding mode to round towards zero. Never increments the digit prior to a discarded fraction (i.e., truncates). Note that this rounding mode never increases the magnitude of the calculated value.
public static final int ROUND_FLOOR
Rounding mode to round towards negative infinity. If the
BigDecimal
is positive, behave as for
ROUND_DOWN
; if negative, behave as for
ROUND_UP
. Note that this rounding mode never
increases the calculated value.
public static final int ROUND_HALF_DOWN
Rounding mode to round towards "nearest neighbor"
unless both neighbors are equidistant, in which case round
down. Behaves as for ROUND_UP
if the discarded
fraction is > 0.5; otherwise, behaves as for
ROUND_DOWN
.
public static final int ROUND_HALF_EVEN
Rounding mode to round towards the "nearest neighbor"
unless both neighbors are equidistant, in which case, round
towards the even neighbor. Behaves as for
ROUND_HALF_UP
if the digit to the left of the
discarded fraction is odd; behaves as for
ROUND_HALF_DOWN
if it's even. Note that this is the
rounding mode that minimizes cumulative error when applied
repeatedly over a sequence of calculations.
public static final int ROUND_HALF_UP
Rounding mode to round towards "nearest neighbor"
unless both neighbors are equidistant, in which case round up.
Behaves as for ROUND_UP
if the discarded fraction is
≥ 0.5; otherwise, behaves as for ROUND_DOWN
. Note
that this is the rounding mode that most of us were taught in
grade school.
public static final int ROUND_UNNECESSARY
Rounding mode to assert that the requested operation has an exact
result, hence no rounding is necessary. If this rounding mode is
specified on an operation that yields an inexact result, an
ArithmeticException
is thrown.
public static final int ROUND_UP
Rounding mode to round away from zero. Always increments the digit prior to a nonzero discarded fraction. Note that this rounding mode never decreases the magnitude of the calculated value.
Fields
public static final BigDecimal ONE
The value 1, with a scale of 0.
public static final BigDecimal TEN
The value 10, with a scale of 0.
public static final BigDecimal ZERO
The value 0, with a scale of 0.
Public Constructors
public BigDecimal (char[] in, int offset, int len)
Translates a character array representation of a
BigDecimal
into a BigDecimal
, accepting the
same sequence of characters as the BigDecimal(String)
constructor, while allowing a subarray to be specified.
Note that if the sequence of characters is already available
within a character array, using this constructor is faster than
converting the char
array to string and using the
BigDecimal(String)
constructor .
Parameters
in  char array that is the source of characters. 

offset  first character in the array to inspect. 
len  number of characters to consider. 
Throws
NumberFormatException  if in is not a valid
representation of a BigDecimal or the defined subarray
is not wholly within in . 

public BigDecimal (char[] in, int offset, int len, MathContext mc)
Translates a character array representation of a
BigDecimal
into a BigDecimal
, accepting the
same sequence of characters as the BigDecimal(String)
constructor, while allowing a subarray to be specified and
with rounding according to the context settings.
Note that if the sequence of characters is already available
within a character array, using this constructor is faster than
converting the char
array to string and using the
BigDecimal(String)
constructor .
Parameters
in  char array that is the source of characters. 

offset  first character in the array to inspect. 
len  number of characters to consider.. 
mc  the context to use. 
Throws
ArithmeticException  if the result is inexact but the
rounding mode is UNNECESSARY . 

NumberFormatException  if in is not a valid
representation of a BigDecimal or the defined subarray
is not wholly within in . 
public BigDecimal (char[] in)
Translates a character array representation of a
BigDecimal
into a BigDecimal
, accepting the
same sequence of characters as the BigDecimal(String)
constructor.
Note that if the sequence of characters is already available
as a character array, using this constructor is faster than
converting the char
array to string and using the
BigDecimal(String)
constructor .
Parameters
in  char array that is the source of characters. 

Throws
NumberFormatException  if in is not a valid
representation of a BigDecimal . 

public BigDecimal (char[] in, MathContext mc)
Translates a character array representation of a
BigDecimal
into a BigDecimal
, accepting the
same sequence of characters as the BigDecimal(String)
constructor and with rounding according to the context
settings.
Note that if the sequence of characters is already available
as a character array, using this constructor is faster than
converting the char
array to string and using the
BigDecimal(String)
constructor .
Parameters
in  char array that is the source of characters. 

mc  the context to use. 
Throws
ArithmeticException  if the result is inexact but the
rounding mode is UNNECESSARY . 

NumberFormatException  if in is not a valid
representation of a BigDecimal . 
public BigDecimal (String val)
Translates the string representation of a BigDecimal
into a BigDecimal
. The string representation consists
of an optional sign, '+'
( '\u002B') or
''
('\u002D'), followed by a sequence of
zero or more decimal digits ("the integer"), optionally
followed by a fraction, optionally followed by an exponent.
The fraction consists of a decimal point followed by zero or more decimal digits. The string must contain at least one digit in either the integer or the fraction. The number formed by the sign, the integer and the fraction is referred to as the significand.
The exponent consists of the character 'e'
('\u0065') or 'E'
('\u0045')
followed by one or more decimal digits. The value of the
exponent must lie between MAX_VALUE
(MIN_VALUE
+1) and MAX_VALUE
, inclusive.
More formally, the strings this constructor accepts are described by the following grammar:
 BigDecimalString:
 Sign_{opt} Significand Exponent_{opt}
 Sign:
+

 Significand:
 IntegerPart
.
FractionPart_{opt}.
FractionPart IntegerPart
 IntegerPart:
 Digits
 FractionPart:
 Digits
 Exponent:
 ExponentIndicator SignedInteger
 ExponentIndicator:
e
E
 SignedInteger:
 Sign_{opt} Digits
 Digits:
 Digit
 Digits Digit
 Digit:
 any character for which
isDigit(char)
returnstrue
, including 0, 1, 2 ...
The scale of the returned BigDecimal
will be the
number of digits in the fraction, or zero if the string
contains no decimal point, subject to adjustment for any
exponent; if the string contains an exponent, the exponent is
subtracted from the scale. The value of the resulting scale
must lie between Integer.MIN_VALUE
and
Integer.MAX_VALUE
, inclusive.
The charactertodigit mapping is provided by digit(char, int)
set to convert to radix 10. The
String may not contain any extraneous characters (whitespace,
for example).
Examples:
The value of the returned BigDecimal
is equal to
significand × 10^{ exponent}.
For each string on the left, the resulting representation
[BigInteger
, scale
] is shown on the right.
"0" [0,0] "0.00" [0,2] "123" [123,0] "123" [123,0] "1.23E3" [123,1] "1.23E+3" [123,1] "12.3E+7" [123,6] "12.0" [120,1] "12.3" [123,1] "0.00123" [123,5] "1.23E12" [123,14] "1234.5E4" [12345,5] "0E+7" [0,7] "0" [0,0]
Note: For values other than float
and
double
NaN and ±Infinity, this constructor is
compatible with the values returned by toString()
and toString()
. This is generally the preferred
way to convert a float
or double
into a
BigDecimal, as it doesn't suffer from the unpredictability of
the BigDecimal(double)
constructor.
Parameters
val  String representation of BigDecimal . 

Throws
NumberFormatException  if val is not a valid
representation of a BigDecimal .


public BigDecimal (String val, MathContext mc)
Translates the string representation of a BigDecimal
into a BigDecimal
, accepting the same strings as the
BigDecimal(String)
constructor, with rounding
according to the context settings.
Parameters
val  string representation of a BigDecimal . 

mc  the context to use. 
Throws
ArithmeticException  if the result is inexact but the
rounding mode is UNNECESSARY . 

NumberFormatException  if val is not a valid
representation of a BigDecimal. 
public BigDecimal (double val)
Translates a double
into a BigDecimal
which
is the exact decimal representation of the double
's
binary floatingpoint value. The scale of the returned
BigDecimal
is the smallest value such that
(10^{scale} × val) is an integer.
Notes:

The results of this constructor can be somewhat unpredictable.
One might assume that writing
new BigDecimal(0.1)
in Java creates aBigDecimal
which is exactly equal to 0.1 (an unscaled value of 1, with a scale of 1), but it is actually equal to 0.1000000000000000055511151231257827021181583404541015625. This is because 0.1 cannot be represented exactly as adouble
(or, for that matter, as a binary fraction of any finite length). Thus, the value that is being passed in to the constructor is not exactly equal to 0.1, appearances notwithstanding. 
The
String
constructor, on the other hand, is perfectly predictable: writingnew BigDecimal("0.1")
creates aBigDecimal
which is exactly equal to 0.1, as one would expect. Therefore, it is generally recommended that the {@linkplain #BigDecimal(String) String constructor} be used in preference to this one. 
When a
double
must be used as a source for aBigDecimal
, note that this constructor provides an exact conversion; it does not give the same result as converting thedouble
to aString
using thetoString(double)
method and then using theBigDecimal(String)
constructor. To get that result, use thestatic
valueOf(double)
method.
Parameters
val  double value to be converted to
BigDecimal . 

Throws
NumberFormatException  if val is infinite or NaN.


public BigDecimal (double val, MathContext mc)
Translates a double
into a BigDecimal
, with
rounding according to the context settings. The scale of the
BigDecimal
is the smallest value such that
(10^{scale} × val) is an integer.
The results of this constructor can be somewhat unpredictable
and its use is generally not recommended; see the notes under
the BigDecimal(double)
constructor.
Parameters
val  double value to be converted to
BigDecimal . 

mc  the context to use. 
Throws
ArithmeticException  if the result is inexact but the RoundingMode is UNNECESSARY. 

NumberFormatException  if val is infinite or NaN. 
public BigDecimal (BigInteger val)
Translates a BigInteger
into a BigDecimal
.
The scale of the BigDecimal
is zero.
Parameters
val  BigInteger value to be converted to
BigDecimal .


public BigDecimal (BigInteger val, MathContext mc)
Translates a BigInteger
into a BigDecimal
rounding according to the context settings. The scale of the
BigDecimal
is zero.
Parameters
val  BigInteger value to be converted to
BigDecimal . 

mc  the context to use. 
Throws
ArithmeticException  if the result is inexact but the
rounding mode is UNNECESSARY . 

public BigDecimal (BigInteger unscaledVal, int scale)
Translates a BigInteger
unscaled value and an
int
scale into a BigDecimal
. The value of
the BigDecimal
is
(unscaledVal × 10^{scale}).
Parameters
unscaledVal  unscaled value of the BigDecimal . 

scale  scale of the BigDecimal .

public BigDecimal (BigInteger unscaledVal, int scale, MathContext mc)
Translates a BigInteger
unscaled value and an
int
scale into a BigDecimal
, with rounding
according to the context settings. The value of the
BigDecimal
is (unscaledVal ×
10^{scale}), rounded according to the
precision
and rounding mode settings.
Parameters
unscaledVal  unscaled value of the BigDecimal . 

scale  scale of the BigDecimal . 
mc  the context to use. 
Throws
ArithmeticException  if the result is inexact but the
rounding mode is UNNECESSARY . 

public BigDecimal (int val)
Translates an int
into a BigDecimal
. The
scale of the BigDecimal
is zero.
Parameters
val  int value to be converted to
BigDecimal . 

public BigDecimal (int val, MathContext mc)
Translates an int
into a BigDecimal
, with
rounding according to the context settings. The scale of the
BigDecimal
, before any rounding, is zero.
Parameters
val  int value to be converted to BigDecimal . 

mc  the context to use. 
Throws
ArithmeticException  if the result is inexact but the
rounding mode is UNNECESSARY . 

public BigDecimal (long val)
Translates a long
into a BigDecimal
. The
scale of the BigDecimal
is zero.
Parameters
val  long value to be converted to BigDecimal . 

public BigDecimal (long val, MathContext mc)
Translates a long
into a BigDecimal
, with
rounding according to the context settings. The scale of the
BigDecimal
, before any rounding, is zero.
Parameters
val  long value to be converted to BigDecimal . 

mc  the context to use. 
Throws
ArithmeticException  if the result is inexact but the
rounding mode is UNNECESSARY . 

Public Methods
public BigDecimal abs (MathContext mc)
Returns a BigDecimal
whose value is the absolute value
of this BigDecimal
, with rounding according to the
context settings.
Parameters
mc  the context to use. 

Returns
abs(this)
, rounded as necessary.
Throws
ArithmeticException  if the result is inexact but the
rounding mode is UNNECESSARY . 

public BigDecimal abs ()
Returns a BigDecimal
whose value is the absolute value
of this BigDecimal
, and whose scale is
this.scale()
.
Returns
abs(this)
public BigDecimal add (BigDecimal augend)
Returns a BigDecimal
whose value is (this +
augend)
, and whose scale is max(this.scale(),
augend.scale())
.
Parameters
augend  value to be added to this BigDecimal . 

Returns
this + augend
public BigDecimal add (BigDecimal augend, MathContext mc)
Returns a BigDecimal
whose value is (this + augend)
,
with rounding according to the context settings.
If either number is zero and the precision setting is nonzero then
the other number, rounded if necessary, is used as the result.
Parameters
augend  value to be added to this BigDecimal . 

mc  the context to use. 
Returns
this + augend
, rounded as necessary.
Throws
ArithmeticException  if the result is inexact but the
rounding mode is UNNECESSARY . 

public byte byteValueExact ()
Converts this BigDecimal
to a byte
, checking
for lost information. If this BigDecimal
has a
nonzero fractional part or is out of the possible range for a
byte
result then an ArithmeticException
is
thrown.
Returns
 this
BigDecimal
converted to abyte
.
Throws
ArithmeticException  if this has a nonzero
fractional part, or will not fit in a byte . 

public int compareTo (BigDecimal val)
Compares this BigDecimal
with the specified
BigDecimal
. Two BigDecimal
objects that are
equal in value but have a different scale (like 2.0 and 2.00)
are considered equal by this method. This method is provided
in preference to individual methods for each of the six boolean
comparison operators (<, ==,
>, >=, !=, <=). The
suggested idiom for performing these comparisons is:
(x.compareTo(y)
<op> 0)
, where
<op> is one of the six comparison operators.
Parameters
val  BigDecimal to which this BigDecimal is
to be compared. 

Returns
 1, 0, or 1 as this
BigDecimal
is numerically less than, equal to, or greater thanval
.
public BigDecimal divide (BigDecimal divisor, int scale, int roundingMode)
Returns a BigDecimal
whose value is (this /
divisor)
, and whose scale is as specified. If rounding must
be performed to generate a result with the specified scale, the
specified rounding mode is applied.
The new divide(BigDecimal, int, RoundingMode)
method
should be used in preference to this legacy method.
Parameters
divisor  value by which this BigDecimal is to be divided. 

scale  scale of the BigDecimal quotient to be returned. 
roundingMode  rounding mode to apply. 
Returns
this / divisor
Throws
ArithmeticException  if divisor is zero,
roundingMode==ROUND_UNNECESSARY and
the specified scale is insufficient to represent the result
of the division exactly. 

IllegalArgumentException  if roundingMode does not
represent a valid rounding mode. 
public BigDecimal divide (BigDecimal divisor, int scale, RoundingMode roundingMode)
Returns a BigDecimal
whose value is (this /
divisor)
, and whose scale is as specified. If rounding must
be performed to generate a result with the specified scale, the
specified rounding mode is applied.
Parameters
divisor  value by which this BigDecimal is to be divided. 

scale  scale of the BigDecimal quotient to be returned. 
roundingMode  rounding mode to apply. 
Returns
this / divisor
Throws
ArithmeticException  if divisor is zero,
roundingMode==RoundingMode.UNNECESSARY and
the specified scale is insufficient to represent the result
of the division exactly. 

public BigDecimal divide (BigDecimal divisor, int roundingMode)
Returns a BigDecimal
whose value is (this /
divisor)
, and whose scale is this.scale()
. If
rounding must be performed to generate a result with the given
scale, the specified rounding mode is applied.
The new divide(BigDecimal, RoundingMode)
method
should be used in preference to this legacy method.
Parameters
divisor  value by which this BigDecimal is to be divided. 

roundingMode  rounding mode to apply. 
Returns
this / divisor
Throws
ArithmeticException  if divisor==0 , or
roundingMode==ROUND_UNNECESSARY and
this.scale() is insufficient to represent the result
of the division exactly. 

IllegalArgumentException  if roundingMode does not
represent a valid rounding mode. 
public BigDecimal divide (BigDecimal divisor, MathContext mc)
Returns a BigDecimal
whose value is (this /
divisor)
, with rounding according to the context settings.
Parameters
divisor  value by which this BigDecimal is to be divided. 

mc  the context to use. 
Returns
this / divisor
, rounded as necessary.
Throws
ArithmeticException  if the result is inexact but the
rounding mode is UNNECESSARY or
mc.precision == 0 and the quotient has a
nonterminating decimal expansion. 

public BigDecimal divide (BigDecimal divisor, RoundingMode roundingMode)
Returns a BigDecimal
whose value is (this /
divisor)
, and whose scale is this.scale()
. If
rounding must be performed to generate a result with the given
scale, the specified rounding mode is applied.
Parameters
divisor  value by which this BigDecimal is to be divided. 

roundingMode  rounding mode to apply. 
Returns
this / divisor
Throws
ArithmeticException  if divisor==0 , or
roundingMode==RoundingMode.UNNECESSARY and
this.scale() is insufficient to represent the result
of the division exactly. 

public BigDecimal divide (BigDecimal divisor)
Returns a BigDecimal
whose value is (this /
divisor)
, and whose preferred scale is (this.scale() 
divisor.scale())
; if the exact quotient cannot be
represented (because it has a nonterminating decimal
expansion) an ArithmeticException
is thrown.
Parameters
divisor  value by which this BigDecimal is to be divided. 

Returns
this / divisor
Throws
ArithmeticException  if the exact quotient does not have a terminating decimal expansion 

public BigDecimal[] divideAndRemainder (BigDecimal divisor, MathContext mc)
Returns a twoelement BigDecimal
array containing the
result of divideToIntegralValue
followed by the result of
remainder
on the two operands calculated with rounding
according to the context settings.
Note that if both the integer quotient and remainder are
needed, this method is faster than using the
divideToIntegralValue
and remainder
methods
separately because the division need only be carried out once.
Parameters
divisor  value by which this BigDecimal is to be divided,
and the remainder computed. 

mc  the context to use. 
Returns
 a two element
BigDecimal
array: the quotient (the result ofdivideToIntegralValue
) is the initial element and the remainder is the final element.
Throws
ArithmeticException  if divisor==0 

ArithmeticException  if the result is inexact but the
rounding mode is UNNECESSARY , or mc.precision
> 0 and the result of this.divideToIntgralValue(divisor) would
require a precision of more than mc.precision digits. 
public BigDecimal[] divideAndRemainder (BigDecimal divisor)
Returns a twoelement BigDecimal
array containing the
result of divideToIntegralValue
followed by the result of
remainder
on the two operands.
Note that if both the integer quotient and remainder are
needed, this method is faster than using the
divideToIntegralValue
and remainder
methods
separately because the division need only be carried out once.
Parameters
divisor  value by which this BigDecimal is to be divided,
and the remainder computed. 

Returns
 a two element
BigDecimal
array: the quotient (the result ofdivideToIntegralValue
) is the initial element and the remainder is the final element.
Throws
ArithmeticException  if divisor==0 

public BigDecimal divideToIntegralValue (BigDecimal divisor, MathContext mc)
Returns a BigDecimal
whose value is the integer part
of (this / divisor)
. Since the integer part of the
exact quotient does not depend on the rounding mode, the
rounding mode does not affect the values returned by this
method. The preferred scale of the result is
(this.scale()  divisor.scale())
. An
ArithmeticException
is thrown if the integer part of
the exact quotient needs more than mc.precision
digits.
Parameters
divisor  value by which this BigDecimal is to be divided. 

mc  the context to use. 
Returns
 The integer part of
this / divisor
.
Throws
ArithmeticException  if divisor==0 

ArithmeticException  if mc.precision > 0 and the result
requires a precision of more than mc.precision digits. 
public BigDecimal divideToIntegralValue (BigDecimal divisor)
Returns a BigDecimal
whose value is the integer part
of the quotient (this / divisor)
rounded down. The
preferred scale of the result is (this.scale() 
divisor.scale())
.
Parameters
divisor  value by which this BigDecimal is to be divided. 

Returns
 The integer part of
this / divisor
.
Throws
ArithmeticException  if divisor==0 

public double doubleValue ()
Converts this BigDecimal
to a double
.
This conversion is similar to the
narrowing primitive conversion from double
to
float
as defined in section 5.1.3 of
The Java™ Language Specification:
if this BigDecimal
has too great a
magnitude represent as a double
, it will be
converted to NEGATIVE_INFINITY
or POSITIVE_INFINITY
as appropriate. Note that even when
the return value is finite, this conversion can lose
information about the precision of the BigDecimal
value.
Returns
 this
BigDecimal
converted to adouble
.
public boolean equals (Object x)
Compares this BigDecimal
with the specified
Object
for equality. Unlike compareTo
, this method considers two
BigDecimal
objects equal only if they are equal in
value and scale (thus 2.0 is not equal to 2.00 when compared by
this method).
Parameters
x  Object to which this BigDecimal is
to be compared. 

Returns
true
if and only if the specifiedObject
is aBigDecimal
whose value and scale are equal to thisBigDecimal
's.
public float floatValue ()
Converts this BigDecimal
to a float
.
This conversion is similar to the
narrowing primitive conversion from double
to
float
as defined in section 5.1.3 of
The Java™ Language Specification:
if this BigDecimal
has too great a
magnitude to represent as a float
, it will be
converted to NEGATIVE_INFINITY
or POSITIVE_INFINITY
as appropriate. Note that even when
the return value is finite, this conversion can lose
information about the precision of the BigDecimal
value.
Returns
 this
BigDecimal
converted to afloat
.
public int hashCode ()
Returns the hash code for this BigDecimal
. Note that
two BigDecimal
objects that are numerically equal but
differ in scale (like 2.0 and 2.00) will generally not
have the same hash code.
Returns
 hash code for this
BigDecimal
.
See Also
public int intValue ()
Converts this BigDecimal
to an int
.
This conversion is analogous to the
narrowing primitive conversion from double
to
short
as defined in section 5.1.3 of
The Java™ Language Specification:
any fractional part of this
BigDecimal
will be discarded, and if the resulting
"BigInteger
" is too big to fit in an
int
, only the loworder 32 bits are returned.
Note that this conversion can lose information about the
overall magnitude and precision of this BigDecimal
value as well as return a result with the opposite sign.
Returns
 this
BigDecimal
converted to anint
.
public int intValueExact ()
Converts this BigDecimal
to an int
, checking
for lost information. If this BigDecimal
has a
nonzero fractional part or is out of the possible range for an
int
result then an ArithmeticException
is
thrown.
Returns
 this
BigDecimal
converted to anint
.
Throws
ArithmeticException  if this has a nonzero
fractional part, or will not fit in an int . 

public long longValue ()
Converts this BigDecimal
to a long
.
This conversion is analogous to the
narrowing primitive conversion from double
to
short
as defined in section 5.1.3 of
The Java™ Language Specification:
any fractional part of this
BigDecimal
will be discarded, and if the resulting
"BigInteger
" is too big to fit in a
long
, only the loworder 64 bits are returned.
Note that this conversion can lose information about the
overall magnitude and precision of this BigDecimal
value as well
as return a result with the opposite sign.
Returns
 this
BigDecimal
converted to along
.
public long longValueExact ()
Converts this BigDecimal
to a long
, checking
for lost information. If this BigDecimal
has a
nonzero fractional part or is out of the possible range for a
long
result then an ArithmeticException
is
thrown.
Returns
 this
BigDecimal
converted to along
.
Throws
ArithmeticException  if this has a nonzero
fractional part, or will not fit in a long . 

public BigDecimal max (BigDecimal val)
Returns the maximum of this BigDecimal
and val
.
Parameters
val  value with which the maximum is to be computed. 

Returns
 the
BigDecimal
whose value is the greater of thisBigDecimal
andval
. If they are equal, as defined by thecompareTo
method,this
is returned.
See Also
public BigDecimal min (BigDecimal val)
Returns the minimum of this BigDecimal
and
val
.
Parameters
val  value with which the minimum is to be computed. 

Returns
 the
BigDecimal
whose value is the lesser of thisBigDecimal
andval
. If they are equal, as defined by thecompareTo
method,this
is returned.
See Also
public BigDecimal movePointLeft (int n)
Returns a BigDecimal
which is equivalent to this one
with the decimal point moved n
places to the left. If
n
is nonnegative, the call merely adds n
to
the scale. If n
is negative, the call is equivalent
to movePointRight(n)
. The BigDecimal
returned by this call has value (this ×
10^{n}) and scale max(this.scale()+n,
0)
.
Parameters
n  number of places to move the decimal point to the left. 

Returns
 a
BigDecimal
which is equivalent to this one with the decimal point movedn
places to the left.
Throws
ArithmeticException  if scale overflows. 

public BigDecimal movePointRight (int n)
Returns a BigDecimal
which is equivalent to this one
with the decimal point moved n
places to the right.
If n
is nonnegative, the call merely subtracts
n
from the scale. If n
is negative, the call
is equivalent to movePointLeft(n)
. The
BigDecimal
returned by this call has value (this
× 10^{n}) and scale max(this.scale()n,
0)
.
Parameters
n  number of places to move the decimal point to the right. 

Returns
 a
BigDecimal
which is equivalent to this one with the decimal point movedn
places to the right.
Throws
ArithmeticException  if scale overflows. 

public BigDecimal multiply (BigDecimal multiplicand, MathContext mc)
Returns a BigDecimal
whose value is (this ×
multiplicand), with rounding according to the context settings.
Parameters
multiplicand  value to be multiplied by this BigDecimal . 

mc  the context to use. 
Returns
this * multiplicand
, rounded as necessary.
Throws
ArithmeticException  if the result is inexact but the
rounding mode is UNNECESSARY . 

public BigDecimal multiply (BigDecimal multiplicand)
Returns a BigDecimal
whose value is (this ×
multiplicand), and whose scale is (this.scale() +
multiplicand.scale())
.
Parameters
multiplicand  value to be multiplied by this BigDecimal . 

Returns
this * multiplicand
public BigDecimal negate ()
Returns a BigDecimal
whose value is (this)
,
and whose scale is this.scale()
.
Returns
this
.
public BigDecimal negate (MathContext mc)
Returns a BigDecimal
whose value is (this)
,
with rounding according to the context settings.
Parameters
mc  the context to use. 

Returns
this
, rounded as necessary.
Throws
ArithmeticException  if the result is inexact but the
rounding mode is UNNECESSARY . 

public BigDecimal plus ()
public BigDecimal plus (MathContext mc)
Returns a BigDecimal
whose value is (+this)
,
with rounding according to the context settings.
The effect of this method is identical to that of the round(MathContext)
method.
Parameters
mc  the context to use. 

Returns
this
, rounded as necessary. A zero result will have a scale of 0.
Throws
ArithmeticException  if the result is inexact but the
rounding mode is UNNECESSARY . 

See Also
public BigDecimal pow (int n, MathContext mc)
Returns a BigDecimal
whose value is
(this^{n}). The current implementation uses
the core algorithm defined in ANSI standard X3.2741996 with
rounding according to the context settings. In general, the
returned numerical value is within two ulps of the exact
numerical value for the chosen precision. Note that future
releases may use a different algorithm with a decreased
allowable error bound and increased allowable exponent range.
The X3.2741996 algorithm is:
 An
ArithmeticException
exception is thrown ifabs(n) > 999999999
mc.precision == 0
andn < 0
mc.precision > 0
andn
has more thanmc.precision
decimal digits
 if
n
is zero,ONE
is returned even ifthis
is zero, otherwise if
n
is positive, the result is calculated via the repeated squaring technique into a single accumulator. The individual multiplications with the accumulator use the same math context settings as inmc
except for a precision increased tomc.precision + elength + 1
whereelength
is the number of decimal digits inn
.  if
n
is negative, the result is calculated as ifn
were positive; this value is then divided into one using the working precision specified above.  The final value from either the positive or negative case is then rounded to the destination precision.
 if
Parameters
n  power to raise this BigDecimal to. 

mc  the context to use. 
Returns
 this^{n} using the ANSI standard X3.2741996 algorithm
Throws
ArithmeticException  if the result is inexact but the
rounding mode is UNNECESSARY , or n is out
of range. 

public BigDecimal pow (int n)
Returns a BigDecimal
whose value is
(this^{n}), The power is computed exactly, to
unlimited precision.
The parameter n
must be in the range 0 through
999999999, inclusive. ZERO.pow(0)
returns ONE
.
Note that future releases may expand the allowable exponent
range of this method.
Parameters
n  power to raise this BigDecimal to. 

Returns
 this^{n}
Throws
ArithmeticException  if n is out of range. 

public int precision ()
Returns the precision of this BigDecimal
. (The
precision is the number of digits in the unscaled value.)
The precision of a zero value is 1.
Returns
 the precision of this
BigDecimal
.
public BigDecimal remainder (BigDecimal divisor)
Returns a BigDecimal
whose value is (this % divisor)
.
The remainder is given by
this.subtract(this.divideToIntegralValue(divisor).multiply(divisor))
.
Note that this is not the modulo operation (the result can be
negative).
Parameters
divisor  value by which this BigDecimal is to be divided. 

Returns
this % divisor
.
Throws
ArithmeticException  if divisor==0 

public BigDecimal remainder (BigDecimal divisor, MathContext mc)
Returns a BigDecimal
whose value is (this %
divisor)
, with rounding according to the context settings.
The MathContext
settings affect the implicit divide
used to compute the remainder. The remainder computation
itself is by definition exact. Therefore, the remainder may
contain more than mc.getPrecision()
digits.
The remainder is given by
this.subtract(this.divideToIntegralValue(divisor,
mc).multiply(divisor))
. Note that this is not the modulo
operation (the result can be negative).
Parameters
divisor  value by which this BigDecimal is to be divided. 

mc  the context to use. 
Returns
this % divisor
, rounded as necessary.
Throws
ArithmeticException  if divisor==0 

ArithmeticException  if the result is inexact but the
rounding mode is UNNECESSARY , or mc.precision
> 0 and the result of this.divideToIntgralValue(divisor) would
require a precision of more than mc.precision digits. 
public BigDecimal round (MathContext mc)
Returns a BigDecimal
rounded according to the
MathContext
settings. If the precision setting is 0 then
no rounding takes place.
The effect of this method is identical to that of the
plus(MathContext)
method.
Parameters
mc  the context to use. 

Returns
 a
BigDecimal
rounded according to theMathContext
settings.
Throws
ArithmeticException  if the rounding mode is
UNNECESSARY and the
BigDecimal operation would require rounding. 

See Also
public int scale ()
Returns the scale of this BigDecimal
. If zero
or positive, the scale is the number of digits to the right of
the decimal point. If negative, the unscaled value of the
number is multiplied by ten to the power of the negation of the
scale. For example, a scale of 3
means the unscaled
value is multiplied by 1000.
Returns
 the scale of this
BigDecimal
.
public BigDecimal scaleByPowerOfTen (int n)
Returns a BigDecimal whose numerical value is equal to
(this
* 10^{n}). The scale of
the result is (this.scale()  n)
.
Parameters
n  the exponent power of ten to scale by 

Returns
 a BigDecimal whose numerical value is equal to
(
this
* 10^{n})
Throws
ArithmeticException  if the scale would be outside the range of a 32bit integer. 

public BigDecimal setScale (int newScale, int roundingMode)
Returns a BigDecimal
whose scale is the specified
value, and whose unscaled value is determined by multiplying or
dividing this BigDecimal
's unscaled value by the
appropriate power of ten to maintain its overall value. If the
scale is reduced by the operation, the unscaled value must be
divided (rather than multiplied), and the value may be changed;
in this case, the specified rounding mode is applied to the
division.
Note that since BigDecimal objects are immutable, calls of
this method do not result in the original object being
modified, contrary to the usual convention of having methods
named setX mutate field X
.
Instead, setScale
returns an object with the proper
scale; the returned object may or may not be newly allocated.
The new setScale(int, RoundingMode)
method should
be used in preference to this legacy method.
Parameters
newScale  scale of the BigDecimal value to be returned. 

roundingMode  The rounding mode to apply. 
Returns
 a
BigDecimal
whose scale is the specified value, and whose unscaled value is determined by multiplying or dividing thisBigDecimal
's unscaled value by the appropriate power of ten to maintain its overall value.
Throws
ArithmeticException  if roundingMode==ROUND_UNNECESSARY
and the specified scaling operation would require
rounding. 

IllegalArgumentException  if roundingMode does not
represent a valid rounding mode. 
public BigDecimal setScale (int newScale)
Returns a BigDecimal
whose scale is the specified
value, and whose value is numerically equal to this
BigDecimal
's. Throws an ArithmeticException
if this is not possible.
This call is typically used to increase the scale, in which
case it is guaranteed that there exists a BigDecimal
of the specified scale and the correct value. The call can
also be used to reduce the scale if the caller knows that the
BigDecimal
has sufficiently many zeros at the end of
its fractional part (i.e., factors of ten in its integer value)
to allow for the rescaling without changing its value.
This method returns the same result as the twoargument
versions of setScale
, but saves the caller the trouble
of specifying a rounding mode in cases where it is irrelevant.
Note that since BigDecimal
objects are immutable,
calls of this method do not result in the original
object being modified, contrary to the usual convention of
having methods named setX mutate field
X
. Instead, setScale
returns an
object with the proper scale; the returned object may or may
not be newly allocated.
Parameters
newScale  scale of the BigDecimal value to be returned. 

Returns
 a
BigDecimal
whose scale is the specified value, and whose unscaled value is determined by multiplying or dividing thisBigDecimal
's unscaled value by the appropriate power of ten to maintain its overall value.
Throws
ArithmeticException  if the specified scaling operation would require rounding. 

public BigDecimal setScale (int newScale, RoundingMode roundingMode)
Returns a BigDecimal
whose scale is the specified
value, and whose unscaled value is determined by multiplying or
dividing this BigDecimal
's unscaled value by the
appropriate power of ten to maintain its overall value. If the
scale is reduced by the operation, the unscaled value must be
divided (rather than multiplied), and the value may be changed;
in this case, the specified rounding mode is applied to the
division.
Note that since BigDecimal objects are immutable, calls of
this method do not result in the original object being
modified, contrary to the usual convention of having methods
named setX mutate field X
.
Instead, setScale
returns an object with the proper
scale; the returned object may or may not be newly allocated.
Parameters
newScale  scale of the BigDecimal value to be returned. 

roundingMode  The rounding mode to apply. 
Returns
 a
BigDecimal
whose scale is the specified value, and whose unscaled value is determined by multiplying or dividing thisBigDecimal
's unscaled value by the appropriate power of ten to maintain its overall value.
Throws
ArithmeticException  if roundingMode==UNNECESSARY
and the specified scaling operation would require
rounding. 

See Also
public short shortValueExact ()
Converts this BigDecimal
to a short
, checking
for lost information. If this BigDecimal
has a
nonzero fractional part or is out of the possible range for a
short
result then an ArithmeticException
is
thrown.
Returns
 this
BigDecimal
converted to ashort
.
Throws
ArithmeticException  if this has a nonzero
fractional part, or will not fit in a short . 

public int signum ()
Returns the signum function of this BigDecimal
.
Returns
 1, 0, or 1 as the value of this
BigDecimal
is negative, zero, or positive.
public BigDecimal stripTrailingZeros ()
Returns a BigDecimal
which is numerically equal to
this one but with any trailing zeros removed from the
representation. For example, stripping the trailing zeros from
the BigDecimal
value 600.0
, which has
[BigInteger
, scale
] components equals to
[6000, 1], yields 6E2
with [BigInteger
,
scale
] components equals to [6, 2]. If
this BigDecimal is numerically equal to zero, then
BigDecimal.ZERO
is returned.
Returns
 a numerically equal
BigDecimal
with any trailing zeros removed.
public BigDecimal subtract (BigDecimal subtrahend)
Returns a BigDecimal
whose value is (this 
subtrahend)
, and whose scale is max(this.scale(),
subtrahend.scale())
.
Parameters
subtrahend  value to be subtracted from this BigDecimal . 

Returns
this  subtrahend
public BigDecimal subtract (BigDecimal subtrahend, MathContext mc)
Returns a BigDecimal
whose value is (this  subtrahend)
,
with rounding according to the context settings.
If subtrahend
is zero then this, rounded if necessary, is used as the
result. If this is zero then the result is subtrahend.negate(mc)
.
Parameters
subtrahend  value to be subtracted from this BigDecimal . 

mc  the context to use. 
Returns
this  subtrahend
, rounded as necessary.
Throws
ArithmeticException  if the result is inexact but the
rounding mode is UNNECESSARY . 

public BigInteger toBigInteger ()
Converts this BigDecimal
to a BigInteger
.
This conversion is analogous to the
narrowing primitive conversion from double
to
long
as defined in section 5.1.3 of
The Java™ Language Specification:
any fractional part of this
BigDecimal
will be discarded. Note that this
conversion can lose information about the precision of the
BigDecimal
value.
To have an exception thrown if the conversion is inexact (in
other words if a nonzero fractional part is discarded), use the
toBigIntegerExact()
method.
Returns
 this
BigDecimal
converted to aBigInteger
.
public BigInteger toBigIntegerExact ()
Converts this BigDecimal
to a BigInteger
,
checking for lost information. An exception is thrown if this
BigDecimal
has a nonzero fractional part.
Returns
 this
BigDecimal
converted to aBigInteger
.
Throws
ArithmeticException  if this has a nonzero
fractional part. 

public String toEngineeringString ()
Returns a string representation of this BigDecimal
,
using engineering notation if an exponent is needed.
Returns a string that represents the BigDecimal
as
described in the toString()
method, except that if
exponential notation is used, the power of ten is adjusted to
be a multiple of three (engineering notation) such that the
integer part of nonzero values will be in the range 1 through
999. If exponential notation is used for zero values, a
decimal point and one or two fractional zero digits are used so
that the scale of the zero value is preserved. Note that
unlike the output of toString()
, the output of this
method is not guaranteed to recover the same [integer,
scale] pair of this BigDecimal
if the output string is
converting back to a BigDecimal
using the {@linkplain #BigDecimal(String) string constructor}. The result of this method meets
the weaker constraint of always producing a numerically equal
result from applying the string constructor to the method's output.
Returns
 string representation of this
BigDecimal
, using engineering notation if an exponent is needed.
public String toPlainString ()
Returns a string representation of this BigDecimal
without an exponent field. For values with a positive scale,
the number of digits to the right of the decimal point is used
to indicate scale. For values with a zero or negative scale,
the resulting string is generated as if the value were
converted to a numerically equal value with zero scale and as
if all the trailing zeros of the zero scale value were present
in the result.
The entire string is prefixed by a minus sign character ''
('\u002D') if the unscaled value is less than
zero. No sign character is prefixed if the unscaled value is
zero or positive.
Note that if the result of this method is passed to the
{@linkplain #BigDecimal(String) string constructor}, only the
numerical value of this BigDecimal
will necessarily be
recovered; the representation of the new BigDecimal
may have a different scale. In particular, if this
BigDecimal
has a negative scale, the string resulting
from this method will have a scale of zero when processed by
the string constructor.
(This method behaves analogously to the toString
method in 1.4 and earlier releases.)
Returns
 a string representation of this
BigDecimal
without an exponent field.
See Also
public String toString ()
Returns the string representation of this BigDecimal
,
using scientific notation if an exponent is needed.
A standard canonical string form of the BigDecimal
is created as though by the following steps: first, the
absolute value of the unscaled value of the BigDecimal
is converted to a string in base ten using the characters
'0'
through '9'
with no leading zeros (except
if its value is zero, in which case a single '0'
character is used).
Next, an adjusted exponent is calculated; this is the
negated scale, plus the number of characters in the converted
unscaled value, less one. That is,
scale+(ulength1)
, where ulength
is the
length of the absolute value of the unscaled value in decimal
digits (its precision).
If the scale is greater than or equal to zero and the
adjusted exponent is greater than or equal to 6
, the
number will be converted to a character form without using
exponential notation. In this case, if the scale is zero then
no decimal point is added and if the scale is positive a
decimal point will be inserted with the scale specifying the
number of characters to the right of the decimal point.
'0'
characters are added to the left of the converted
unscaled value as necessary. If no character precedes the
decimal point after this insertion then a conventional
'0'
character is prefixed.
Otherwise (that is, if the scale is negative, or the
adjusted exponent is less than 6
), the number will be
converted to a character form using exponential notation. In
this case, if the converted BigInteger
has more than
one digit a decimal point is inserted after the first digit.
An exponent in character form is then suffixed to the converted
unscaled value (perhaps with inserted decimal point); this
comprises the letter 'E'
followed immediately by the
adjusted exponent converted to a character form. The latter is
in base ten, using the characters '0'
through
'9'
with no leading zeros, and is always prefixed by a
sign character ''
('\u002D') if the
adjusted exponent is negative, '+'
('\u002B') otherwise).
Finally, the entire string is prefixed by a minus sign
character ''
('\u002D') if the unscaled
value is less than zero. No sign character is prefixed if the
unscaled value is zero or positive.
Examples:
For each representation [unscaled value, scale] on the left, the resulting string is shown on the right.
[123,0] "123" [123,0] "123" [123,1] "1.23E+3" [123,3] "1.23E+5" [123,1] "12.3" [123,5] "0.00123" [123,10] "1.23E8" [123,12] "1.23E10"Notes:
 There is a onetoone mapping between the distinguishable
BigDecimal
values and the result of this conversion. That is, every distinguishableBigDecimal
value (unscaled value and scale) has a unique string representation as a result of usingtoString
. If that string representation is converted back to aBigDecimal
using theBigDecimal(String)
constructor, then the original value will be recovered.  The string produced for a given number is always the same;
it is not affected by locale. This means that it can be used
as a canonical string representation for exchanging decimal
data, or as a key for a Hashtable, etc. Localesensitive
number formatting and parsing is handled by the
NumberFormat
class and its subclasses.  The
toEngineeringString()
method may be used for presenting numbers with exponents in engineering notation, and thesetScale
method may be used for rounding aBigDecimal
so it has a known number of digits after the decimal point.  The digittocharacter mapping provided by
Character.forDigit
is used.
Returns
 string representation of this
BigDecimal
.
public BigDecimal ulp ()
Returns the size of an ulp, a unit in the last place, of this
BigDecimal
. An ulp of a nonzero BigDecimal
value is the positive distance between this value and the
BigDecimal
value next larger in magnitude with the
same number of digits. An ulp of a zero value is numerically
equal to 1 with the scale of this
. The result is
stored with the same scale as this
so the result
for zero and nonzero values is equal to [1,
this.scale()]
.
Returns
 the size of an ulp of
this
public BigInteger unscaledValue ()
Returns a BigInteger
whose value is the unscaled
value of this BigDecimal
. (Computes (this *
10^{this.scale()}).)
Returns
 the unscaled value of this
BigDecimal
.
public static BigDecimal valueOf (double val)
Translates a double
into a BigDecimal
, using
the double
's canonical string representation provided
by the toString(double)
method.
Note: This is generally the preferred way to convert
a double
(or float
) into a
BigDecimal
, as the value returned is equal to that
resulting from constructing a BigDecimal
from the
result of using toString(double)
.
Parameters
val  double to convert to a BigDecimal . 

Returns
 a
BigDecimal
whose value is equal to or approximately equal to the value ofval
.
Throws
NumberFormatException  if val is infinite or NaN. 

public static BigDecimal valueOf (long val)
Translates a long
value into a BigDecimal
with a scale of zero. This "static factory method"
is provided in preference to a (long
) constructor
because it allows for reuse of frequently used
BigDecimal
values.
Parameters
val  value of the BigDecimal . 

Returns
 a
BigDecimal
whose value isval
.
public static BigDecimal valueOf (long unscaledVal, int scale)
Translates a long
unscaled value and an
int
scale into a BigDecimal
. This
"static factory method" is provided in preference to
a (long
, int
) constructor because it
allows for reuse of frequently used BigDecimal
values..
Parameters
unscaledVal  unscaled value of the BigDecimal . 

scale  scale of the BigDecimal . 
Returns
 a
BigDecimal
whose value is (unscaledVal × 10^{scale}).