org.apache.commons.lang3.math

## Class NumberUtils

- java.lang.Object
- - org.apache.commons.lang3.math.NumberUtils

-     public class NumberUtils
      extends Object

  Provides extra functionality for Java Number classes.

  Since:
    2.0
  Version:
    $Id: NumberUtils.java 1582585 2014-03-28 03:10:27Z niallp $

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static Byte` | `BYTE_MINUS_ONE` Reusable Byte constant for minus one.
    `static Byte` | `BYTE_ONE` Reusable Byte constant for one.
    `static Byte` | `BYTE_ZERO` Reusable Byte constant for zero.
    `static Double` | `DOUBLE_MINUS_ONE` Reusable Double constant for minus one.
    `static Double` | `DOUBLE_ONE` Reusable Double constant for one.
    `static Double` | `DOUBLE_ZERO` Reusable Double constant for zero.
    `static Float` | `FLOAT_MINUS_ONE` Reusable Float constant for minus one.
    `static Float` | `FLOAT_ONE` Reusable Float constant for one.
    `static Float` | `FLOAT_ZERO` Reusable Float constant for zero.
    `static Integer` | `INTEGER_MINUS_ONE` Reusable Integer constant for minus one.
    `static Integer` | `INTEGER_ONE` Reusable Integer constant for one.
    `static Integer` | `INTEGER_ZERO` Reusable Integer constant for zero.
    `static Long` | `LONG_MINUS_ONE` Reusable Long constant for minus one.
    `static Long` | `LONG_ONE` Reusable Long constant for one.
    `static Long` | `LONG_ZERO` Reusable Long constant for zero.
    `static Short` | `SHORT_MINUS_ONE` Reusable Short constant for minus one.
    `static Short` | `SHORT_ONE` Reusable Short constant for one.
    `static Short` | `SHORT_ZERO` Reusable Short constant for zero.

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `NumberUtils()` `NumberUtils` instances should NOT be constructed in standard programming.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `static BigDecimal` | `createBigDecimal(String str)` Convert a `String` to a `BigDecimal`.
    `static BigInteger` | `createBigInteger(String str)` Convert a `String` to a `BigInteger`; since 3.2 it handles hex (0x or #) and octal (0) notations.
    `static Double` | `createDouble(String str)` Convert a `String` to a `Double`.
    `static Float` | `createFloat(String str)` Convert a `String` to a `Float`.
    `static Integer` | `createInteger(String str)` Convert a `String` to a `Integer`, handling hex (0xhhhh) and octal (0dddd) notations.
    `static Long` | `createLong(String str)` Convert a `String` to a `Long`; since 3.1 it handles hex (0Xhhhh) and octal (0ddd) notations.
    `static Number` | `createNumber(String str)` Turns a string value into a java.lang.Number.
    `static boolean` | `isDigits(String str)` Checks whether the `String` contains only digit characters.
    `static boolean` | `isNumber(String str)` Checks whether the String a valid Java number.
    `static byte` | `max(byte[] array)` Returns the maximum value in an array.
    `static byte` | `max(byte a, byte b, byte c)` Gets the maximum of three `byte` values.
    `static double` | `max(double[] array)` Returns the maximum value in an array.
    `static double` | `max(double a, double b, double c)` Gets the maximum of three `double` values.
    `static float` | `max(float[] array)` Returns the maximum value in an array.
    `static float` | `max(float a, float b, float c)` Gets the maximum of three `float` values.
    `static int` | `max(int[] array)` Returns the maximum value in an array.
    `static int` | `max(int a, int b, int c)` Gets the maximum of three `int` values.
    `static long` | `max(long[] array)` Returns the maximum value in an array.
    `static long` | `max(long a, long b, long c)` Gets the maximum of three `long` values.
    `static short` | `max(short[] array)` Returns the maximum value in an array.
    `static short` | `max(short a, short b, short c)` Gets the maximum of three `short` values.
    `static byte` | `min(byte[] array)` Returns the minimum value in an array.
    `static byte` | `min(byte a, byte b, byte c)` Gets the minimum of three `byte` values.
    `static double` | `min(double[] array)` Returns the minimum value in an array.
    `static double` | `min(double a, double b, double c)` Gets the minimum of three `double` values.
    `static float` | `min(float[] array)` Returns the minimum value in an array.
    `static float` | `min(float a, float b, float c)` Gets the minimum of three `float` values.
    `static int` | `min(int[] array)` Returns the minimum value in an array.
    `static int` | `min(int a, int b, int c)` Gets the minimum of three `int` values.
    `static long` | `min(long[] array)` Returns the minimum value in an array.
    `static long` | `min(long a, long b, long c)` Gets the minimum of three `long` values.
    `static short` | `min(short[] array)` Returns the minimum value in an array.
    `static short` | `min(short a, short b, short c)` Gets the minimum of three `short` values.
    `static byte` | `toByte(String str)` Convert a `String` to a `byte`, returning `zero` if the conversion fails.
    `static byte` | `toByte(String str, byte defaultValue)` Convert a `String` to a `byte`, returning a default value if the conversion fails.
    `static double` | `toDouble(String str)` Convert a `String` to a `double`, returning `0.0d` if the conversion fails.
    `static double` | `toDouble(String str, double defaultValue)` Convert a `String` to a `double`, returning a default value if the conversion fails.
    `static float` | `toFloat(String str)` Convert a `String` to a `float`, returning `0.0f` if the conversion fails.
    `static float` | `toFloat(String str, float defaultValue)` Convert a `String` to a `float`, returning a default value if the conversion fails.
    `static int` | `toInt(String str)` Convert a `String` to an `int`, returning `zero` if the conversion fails.
    `static int` | `toInt(String str, int defaultValue)` Convert a `String` to an `int`, returning a default value if the conversion fails.
    `static long` | `toLong(String str)` Convert a `String` to a `long`, returning `zero` if the conversion fails.
    `static long` | `toLong(String str, long defaultValue)` Convert a `String` to a `long`, returning a default value if the conversion fails.
    `static short` | `toShort(String str)` Convert a `String` to a `short`, returning `zero` if the conversion fails.
    `static short` | `toShort(String str, short defaultValue)` Convert a `String` to an `short`, returning a default value if the conversion fails.

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Field Detail

    - #### LONG_ZERO

          public static final Long LONG_ZERO

      Reusable Long constant for zero.

    - #### LONG_ONE

          public static final Long LONG_ONE

      Reusable Long constant for one.

    - #### LONG_MINUS_ONE

          public static final Long LONG_MINUS_ONE

      Reusable Long constant for minus one.

    - #### INTEGER_ZERO

          public static final Integer INTEGER_ZERO

      Reusable Integer constant for zero.

    - #### INTEGER_ONE

          public static final Integer INTEGER_ONE

      Reusable Integer constant for one.

    - #### INTEGER_MINUS_ONE

          public static final Integer INTEGER_MINUS_ONE

      Reusable Integer constant for minus one.

    - #### SHORT_ZERO

          public static final Short SHORT_ZERO

      Reusable Short constant for zero.

    - #### SHORT_ONE

          public static final Short SHORT_ONE

      Reusable Short constant for one.

    - #### SHORT_MINUS_ONE

          public static final Short SHORT_MINUS_ONE

      Reusable Short constant for minus one.

    - #### BYTE_ZERO

          public static final Byte BYTE_ZERO

      Reusable Byte constant for zero.

    - #### BYTE_ONE

          public static final Byte BYTE_ONE

      Reusable Byte constant for one.

    - #### BYTE_MINUS_ONE

          public static final Byte BYTE_MINUS_ONE

      Reusable Byte constant for minus one.

    - #### DOUBLE_ZERO

          public static final Double DOUBLE_ZERO

      Reusable Double constant for zero.

    - #### DOUBLE_ONE

          public static final Double DOUBLE_ONE

      Reusable Double constant for one.

    - #### DOUBLE_MINUS_ONE

          public static final Double DOUBLE_MINUS_ONE

      Reusable Double constant for minus one.

    - #### FLOAT_ZERO

          public static final Float FLOAT_ZERO

      Reusable Float constant for zero.

    - #### FLOAT_ONE

          public static final Float FLOAT_ONE

      Reusable Float constant for one.

    - #### FLOAT_MINUS_ONE

          public static final Float FLOAT_MINUS_ONE

      Reusable Float constant for minus one.

  - ### Constructor Detail

    - #### NumberUtils

          public NumberUtils()

      `NumberUtils` instances should NOT be constructed in standard programming. Instead, the class should be used as `NumberUtils.toInt("6");`.

      This constructor is public to permit tools that require a JavaBean instance to operate.

  - ### Method Detail

    - #### toInt

          public static int toInt(String str)

      Convert a `String` to an `int`, returning `zero` if the conversion fails.

      If the string is `null`, `zero` is returned.

             NumberUtils.toInt(null) = 0
             NumberUtils.toInt("")   = 0
             NumberUtils.toInt("1")  = 1

      Parameters:
        `str` - the string to convert, may be null
      Returns:
        the int represented by the string, or `zero` if conversion fails
      Since:
        2.1

    - #### toInt

          public static int toInt(String str,
                  int defaultValue)

      Convert a `String` to an `int`, returning a default value if the conversion fails.

      If the string is `null`, the default value is returned.

             NumberUtils.toInt(null, 1) = 1
             NumberUtils.toInt("", 1)   = 1
             NumberUtils.toInt("1", 0)  = 1

      Parameters:
        `str` - the string to convert, may be null
        `defaultValue` - the default value
      Returns:
        the int represented by the string, or the default if conversion fails
      Since:
        2.1

    - #### toLong

          public static long toLong(String str)

      Convert a `String` to a `long`, returning `zero` if the conversion fails.

      If the string is `null`, `zero` is returned.

             NumberUtils.toLong(null) = 0L
             NumberUtils.toLong("")   = 0L
             NumberUtils.toLong("1")  = 1L

      Parameters:
        `str` - the string to convert, may be null
      Returns:
        the long represented by the string, or `0` if conversion fails
      Since:
        2.1

    - #### toLong

          public static long toLong(String str,
                    long defaultValue)

      Convert a `String` to a `long`, returning a default value if the conversion fails.

      If the string is `null`, the default value is returned.

             NumberUtils.toLong(null, 1L) = 1L
             NumberUtils.toLong("", 1L)   = 1L
             NumberUtils.toLong("1", 0L)  = 1L

      Parameters:
        `str` - the string to convert, may be null
        `defaultValue` - the default value
      Returns:
        the long represented by the string, or the default if conversion fails
      Since:
        2.1

    - #### toFloat

          public static float toFloat(String str)

      Convert a `String` to a `float`, returning `0.0f` if the conversion fails.

      If the string `str` is `null`, `0.0f` is returned.

             NumberUtils.toFloat(null)   = 0.0f
             NumberUtils.toFloat("")     = 0.0f
             NumberUtils.toFloat("1.5")  = 1.5f

      Parameters:
        `str` - the string to convert, may be `null`
      Returns:
        the float represented by the string, or `0.0f` if conversion fails
      Since:
        2.1

    - #### toFloat

          public static float toFloat(String str,
                      float defaultValue)

      Convert a `String` to a `float`, returning a default value if the conversion fails.

      If the string `str` is `null`, the default value is returned.

             NumberUtils.toFloat(null, 1.1f)   = 1.0f
             NumberUtils.toFloat("", 1.1f)     = 1.1f
             NumberUtils.toFloat("1.5", 0.0f)  = 1.5f

      Parameters:
        `str` - the string to convert, may be `null`
        `defaultValue` - the default value
      Returns:
        the float represented by the string, or defaultValue if conversion fails
      Since:
        2.1

    - #### toDouble

          public static double toDouble(String str)

      Convert a `String` to a `double`, returning `0.0d` if the conversion fails.

      If the string `str` is `null`, `0.0d` is returned.

             NumberUtils.toDouble(null)   = 0.0d
             NumberUtils.toDouble("")     = 0.0d
             NumberUtils.toDouble("1.5")  = 1.5d

      Parameters:
        `str` - the string to convert, may be `null`
      Returns:
        the double represented by the string, or `0.0d` if conversion fails
      Since:
        2.1

    - #### toDouble

          public static double toDouble(String str,
                        double defaultValue)

      Convert a `String` to a `double`, returning a default value if the conversion fails.

      If the string `str` is `null`, the default value is returned.

             NumberUtils.toDouble(null, 1.1d)   = 1.1d
             NumberUtils.toDouble("", 1.1d)     = 1.1d
             NumberUtils.toDouble("1.5", 0.0d)  = 1.5d

      Parameters:
        `str` - the string to convert, may be `null`
        `defaultValue` - the default value
      Returns:
        the double represented by the string, or defaultValue if conversion fails
      Since:
        2.1

    - #### toByte

          public static byte toByte(String str)

      Convert a `String` to a `byte`, returning `zero` if the conversion fails.

      If the string is `null`, `zero` is returned.

             NumberUtils.toByte(null) = 0
             NumberUtils.toByte("")   = 0
             NumberUtils.toByte("1")  = 1

      Parameters:
        `str` - the string to convert, may be null
      Returns:
        the byte represented by the string, or `zero` if conversion fails
      Since:
        2.5

    - #### toByte

          public static byte toByte(String str,
                    byte defaultValue)

      Convert a `String` to a `byte`, returning a default value if the conversion fails.

      If the string is `null`, the default value is returned.

             NumberUtils.toByte(null, 1) = 1
             NumberUtils.toByte("", 1)   = 1
             NumberUtils.toByte("1", 0)  = 1

      Parameters:
        `str` - the string to convert, may be null
        `defaultValue` - the default value
      Returns:
        the byte represented by the string, or the default if conversion fails
      Since:
        2.5

    - #### toShort

          public static short toShort(String str)

      Convert a `String` to a `short`, returning `zero` if the conversion fails.

      If the string is `null`, `zero` is returned.

             NumberUtils.toShort(null) = 0
             NumberUtils.toShort("")   = 0
             NumberUtils.toShort("1")  = 1

      Parameters:
        `str` - the string to convert, may be null
      Returns:
        the short represented by the string, or `zero` if conversion fails
      Since:
        2.5

    - #### toShort

          public static short toShort(String str,
                      short defaultValue)

      Convert a `String` to an `short`, returning a default value if the conversion fails.

      If the string is `null`, the default value is returned.

             NumberUtils.toShort(null, 1) = 1
             NumberUtils.toShort("", 1)   = 1
             NumberUtils.toShort("1", 0)  = 1

      Parameters:
        `str` - the string to convert, may be null
        `defaultValue` - the default value
      Returns:
        the short represented by the string, or the default if conversion fails
      Since:
        2.5

    - #### createNumber

          public static Number createNumber(String str)
                                     throws NumberFormatException

      Turns a string value into a java.lang.Number.

      If the string starts with `0x` or `-0x` (lower or upper case) or `#` or `-#`, it will be interpreted as a hexadecimal Integer - or Long, if the number of digits after the prefix is more than 8 - or BigInteger if there are more than 16 digits.

      Then, the value is examined for a type qualifier on the end, i.e. one of `'f','F','d','D','l','L'`. If it is found, it starts trying to create successively larger types from the type specified until one is found that can represent the value.

      If a type specifier is not found, it will check for a decimal point and then try successively larger types from `Integer` to `BigInteger` and from `Float` to `BigDecimal`.

      Integral values with a leading `0` will be interpreted as octal; the returned number will be Integer, Long or BigDecimal as appropriate.

      Returns `null` if the string is `null`.

      This method does not trim the input string, i.e., strings with leading or trailing spaces will generate NumberFormatExceptions.

      Parameters:
        `str` - String containing a number, may be null
      Returns:
        Number created from the string (or null if the input is null)
      Throws:
        `NumberFormatException` - if the value cannot be converted

    - #### createFloat

          public static Float createFloat(String str)

      Convert a `String` to a `Float`.

      Returns `null` if the string is `null`.

      Parameters:
        `str` - a `String` to convert, may be null
      Returns:
        converted `Float` (or null if the input is null)
      Throws:
        `NumberFormatException` - if the value cannot be converted

    - #### createDouble

          public static Double createDouble(String str)

      Convert a `String` to a `Double`.

      Returns `null` if the string is `null`.

      Parameters:
        `str` - a `String` to convert, may be null
      Returns:
        converted `Double` (or null if the input is null)
      Throws:
        `NumberFormatException` - if the value cannot be converted

    - #### createInteger

          public static Integer createInteger(String str)

      Convert a `String` to a `Integer`, handling hex (0xhhhh) and octal (0dddd) notations. N.B. a leading zero means octal; spaces are not trimmed.

      Returns `null` if the string is `null`.

      Parameters:
        `str` - a `String` to convert, may be null
      Returns:
        converted `Integer` (or null if the input is null)
      Throws:
        `NumberFormatException` - if the value cannot be converted

    - #### createLong

          public static Long createLong(String str)

      Convert a `String` to a `Long`; since 3.1 it handles hex (0Xhhhh) and octal (0ddd) notations. N.B. a leading zero means octal; spaces are not trimmed.

      Returns `null` if the string is `null`.

      Parameters:
        `str` - a `String` to convert, may be null
      Returns:
        converted `Long` (or null if the input is null)
      Throws:
        `NumberFormatException` - if the value cannot be converted

    - #### createBigInteger

          public static BigInteger createBigInteger(String str)

      Convert a `String` to a `BigInteger`; since 3.2 it handles hex (0x or #) and octal (0) notations.

      Returns `null` if the string is `null`.

      Parameters:
        `str` - a `String` to convert, may be null
      Returns:
        converted `BigInteger` (or null if the input is null)
      Throws:
        `NumberFormatException` - if the value cannot be converted

    - #### createBigDecimal

          public static BigDecimal createBigDecimal(String str)

      Convert a `String` to a `BigDecimal`.

      Returns `null` if the string is `null`.

      Parameters:
        `str` - a `String` to convert, may be null
      Returns:
        converted `BigDecimal` (or null if the input is null)
      Throws:
        `NumberFormatException` - if the value cannot be converted

    - #### min

          public static long min(long[] array)

      Returns the minimum value in an array.

      Parameters:
        `array` - an array, must not be null or empty
      Returns:
        the minimum value in the array
      Throws:
        `IllegalArgumentException` - if `array` is `null`
        `IllegalArgumentException` - if `array` is empty

    - #### min

          public static int min(int[] array)

      Returns the minimum value in an array.

      Parameters:
        `array` - an array, must not be null or empty
      Returns:
        the minimum value in the array
      Throws:
        `IllegalArgumentException` - if `array` is `null`
        `IllegalArgumentException` - if `array` is empty

    - #### min

          public static short min(short[] array)

      Returns the minimum value in an array.

      Parameters:
        `array` - an array, must not be null or empty
      Returns:
        the minimum value in the array
      Throws:
        `IllegalArgumentException` - if `array` is `null`
        `IllegalArgumentException` - if `array` is empty

    - #### min

          public static byte min(byte[] array)

      Returns the minimum value in an array.

      Parameters:
        `array` - an array, must not be null or empty
      Returns:
        the minimum value in the array
      Throws:
        `IllegalArgumentException` - if `array` is `null`
        `IllegalArgumentException` - if `array` is empty

    - #### min

          public static double min(double[] array)

      Returns the minimum value in an array.

      Parameters:
        `array` - an array, must not be null or empty
      Returns:
        the minimum value in the array
      Throws:
        `IllegalArgumentException` - if `array` is `null`
        `IllegalArgumentException` - if `array` is empty
      See Also:
        `IEEE754rUtils for a version of this method that handles NaN differently`

    - #### min

          public static float min(float[] array)

      Returns the minimum value in an array.

      Parameters:
        `array` - an array, must not be null or empty
      Returns:
        the minimum value in the array
      Throws:
        `IllegalArgumentException` - if `array` is `null`
        `IllegalArgumentException` - if `array` is empty
      See Also:
        `IEEE754rUtils for a version of this method that handles NaN differently`

    - #### max

          public static long max(long[] array)

      Returns the maximum value in an array.

      Parameters:
        `array` - an array, must not be null or empty
      Returns:
        the minimum value in the array
      Throws:
        `IllegalArgumentException` - if `array` is `null`
        `IllegalArgumentException` - if `array` is empty

    - #### max

          public static int max(int[] array)

      Returns the maximum value in an array.

      Parameters:
        `array` - an array, must not be null or empty
      Returns:
        the minimum value in the array
      Throws:
        `IllegalArgumentException` - if `array` is `null`
        `IllegalArgumentException` - if `array` is empty

    - #### max

          public static short max(short[] array)

      Returns the maximum value in an array.

      Parameters:
        `array` - an array, must not be null or empty
      Returns:
        the minimum value in the array
      Throws:
        `IllegalArgumentException` - if `array` is `null`
        `IllegalArgumentException` - if `array` is empty

    - #### max

          public static byte max(byte[] array)

      Returns the maximum value in an array.

      Parameters:
        `array` - an array, must not be null or empty
      Returns:
        the minimum value in the array
      Throws:
        `IllegalArgumentException` - if `array` is `null`
        `IllegalArgumentException` - if `array` is empty

    - #### max

          public static double max(double[] array)

      Returns the maximum value in an array.

      Parameters:
        `array` - an array, must not be null or empty
      Returns:
        the minimum value in the array
      Throws:
        `IllegalArgumentException` - if `array` is `null`
        `IllegalArgumentException` - if `array` is empty
      See Also:
        `IEEE754rUtils for a version of this method that handles NaN differently`

    - #### max

          public static float max(float[] array)

      Returns the maximum value in an array.

      Parameters:
        `array` - an array, must not be null or empty
      Returns:
        the minimum value in the array
      Throws:
        `IllegalArgumentException` - if `array` is `null`
        `IllegalArgumentException` - if `array` is empty
      See Also:
        `IEEE754rUtils for a version of this method that handles NaN differently`

    - #### min

          public static long min(long a,
                 long b,
                 long c)

      Gets the minimum of three `long` values.

      Parameters:
        `a` - value 1
        `b` - value 2
        `c` - value 3
      Returns:
        the smallest of the values

    - #### min

          public static int min(int a,
                int b,
                int c)

      Gets the minimum of three `int` values.

      Parameters:
        `a` - value 1
        `b` - value 2
        `c` - value 3
      Returns:
        the smallest of the values

    - #### min

          public static short min(short a,
                  short b,
                  short c)

      Gets the minimum of three `short` values.

      Parameters:
        `a` - value 1
        `b` - value 2
        `c` - value 3
      Returns:
        the smallest of the values

    - #### min

          public static byte min(byte a,
                 byte b,
                 byte c)

      Gets the minimum of three `byte` values.

      Parameters:
        `a` - value 1
        `b` - value 2
        `c` - value 3
      Returns:
        the smallest of the values

    - #### min

          public static double min(double a,
                   double b,
                   double c)

      Gets the minimum of three `double` values.

      If any value is `NaN`, `NaN` is returned. Infinity is handled.

      Parameters:
        `a` - value 1
        `b` - value 2
        `c` - value 3
      Returns:
        the smallest of the values
      See Also:
        `for a version of this method that handles NaN differently`

    - #### min

          public static float min(float a,
                  float b,
                  float c)

      Gets the minimum of three `float` values.

      If any value is `NaN`, `NaN` is returned. Infinity is handled.

      Parameters:
        `a` - value 1
        `b` - value 2
        `c` - value 3
      Returns:
        the smallest of the values
      See Also:
        `for a version of this method that handles NaN differently`

    - #### max

          public static long max(long a,
                 long b,
                 long c)

      Gets the maximum of three `long` values.

      Parameters:
        `a` - value 1
        `b` - value 2
        `c` - value 3
      Returns:
        the largest of the values

    - #### max

          public static int max(int a,
                int b,
                int c)

      Gets the maximum of three `int` values.

      Parameters:
        `a` - value 1
        `b` - value 2
        `c` - value 3
      Returns:
        the largest of the values

    - #### max

          public static short max(short a,
                  short b,
                  short c)

      Gets the maximum of three `short` values.

      Parameters:
        `a` - value 1
        `b` - value 2
        `c` - value 3
      Returns:
        the largest of the values

    - #### max

          public static byte max(byte a,
                 byte b,
                 byte c)

      Gets the maximum of three `byte` values.

      Parameters:
        `a` - value 1
        `b` - value 2
        `c` - value 3
      Returns:
        the largest of the values

    - #### max

          public static double max(double a,
                   double b,
                   double c)

      Gets the maximum of three `double` values.

      If any value is `NaN`, `NaN` is returned. Infinity is handled.

      Parameters:
        `a` - value 1
        `b` - value 2
        `c` - value 3
      Returns:
        the largest of the values
      See Also:
        `for a version of this method that handles NaN differently`

    - #### max

          public static float max(float a,
                  float b,
                  float c)

      Gets the maximum of three `float` values.

      If any value is `NaN`, `NaN` is returned. Infinity is handled.

      Parameters:
        `a` - value 1
        `b` - value 2
        `c` - value 3
      Returns:
        the largest of the values
      See Also:
        `for a version of this method that handles NaN differently`

    - #### isDigits

          public static boolean isDigits(String str)

      Checks whether the `String` contains only digit characters.

      `Null` and empty String will return `false`.

      Parameters:
        `str` - the `String` to check
      Returns:
        `true` if str contains only Unicode numeric

    - #### isNumber

          public static boolean isNumber(String str)

      Checks whether the String a valid Java number.

      Valid numbers include hexadecimal marked with the `0x` qualifier, scientific notation and numbers marked with a type qualifier (e.g. 123L).

      `Null` and empty String will return `false`.

      Parameters:
        `str` - the `String` to check
      Returns:
        `true` if the string is a correctly formatted number
      Since:
        3.3 the code supports hex `0Xhhh` and octal `0ddd` validation

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