How to use the unsigned Integer in Java 8 and Java 9

Question

In the Oracle  quot Primitive data types quot  page  it mentions that Java 8 adds support for unsigned ints and longs   int  By default  the int data type is a 32-bit signed two s complement integer  which has a minimum value of -231 and a maximum value of 231-1  In Java SE 8 and later  you can use the int data type to represent an unsigned 32-bit integer  which has a minimum value of 0 and a maximum value of 232-1  Use the Integer class to use int data type as an unsigned integer  See the section The Number Classes for more information  Static methods like compareUnsigned  divideUnsigned etc have been added to the Integer class to support the arithmetic operations for unsigned integers  long  The long data type is a 64-bit two s complement integer  The signed long has a minimum value of -263 and a maximum value of 263-1  In Java SE 8 and later  you can use the long data type to represent an unsigned 64-bit long  which has a minimum value of 0 and a maximum value of 264-1  Use this data type when you need a range of values wider than those provided by int  The Long class also contains methods like compareUnsigned  divideUnsigned etc to support arithmetic operations for unsigned long   However  I find no way to declare an unsigned long or integer  The following code  for example  gives a compiler error message of  quot the literal is out of range quot   I m using Java 8  of course   when it should be in range  the value assigned is precisely 264-1   public class Foo       static long values   18446744073709551615L           public static void main String   args           System out println values              So  is there any way to declare an unsigned int or long

User · Answer

If using a third party library is an option, there is jOOU (a spin off library from jOOQ), which offers wrapper types for unsigned integer numbers in Java. That's not exactly the same thing as having primitive type (and thus byte code) support for unsigned types, but perhaps it's still good enough for your use-case.

import static org.joou.Unsigned.*;

// and then...
UByte    b = ubyte(1);
UShort   s = ushort(1);
UInteger i = uint(1);
ULong    l = ulong(1);

All of these types extend java.lang.Number and can be converted into higher-order primitive types and BigInteger.

(Disclaimer: I work for the company behind these libraries)

User · Answer

There is no way how to declare an unsigned long or int in Java 8 or Java 9  But some methods treat them as if they were unsigned  for example   static long values   Long parseUnsignedLong  123456789012345678      but this is not declaration of the variable

User · Answer

Per the documentation you posted  and this blog post - there s no difference when declaring the primitive between an unsigned int long and a signed one   The  new support  is the addition of the static methods in the Integer and Long classes  e g  Integer divideUnsigned   If you re not using those methods  your  unsigned  long above 2 63-1 is just a plain old long with a negative value   From a quick skim  it doesn t look like there s a way to declare integer constants in the range outside of   - 2 31-1  or   - 2 63-1 for longs   You would have to manually compute the negative value corresponding to your out-of-range positive value

User · Answer

Well  even in Java 8  long and int are still signed  only some methods treat them as if they were unsigned  If you want to write unsigned long literal like that  you can do  static long values   Long parseUnsignedLong  18446744073709551615     public static void main String   args        System out println values      -1     System out println Long toUnsignedString values       18446744073709551615

User · Answer

Java 8     int vInt   Integer parseUnsignedInt  4294967295        System out println vInt      -1     String sInt   Integer toUnsignedString vInt       System out println sInt      4294967295      long vLong   Long parseUnsignedLong  18446744073709551615        System out println vLong      -1     String sLong   Long toUnsignedString vLong       System out println sLong      18446744073709551615         Guava 18 0     int vIntGu   UnsignedInts parseUnsignedInt UnsignedInteger MAX VALUE toString         System out println vIntGu      -1     String sIntGu   UnsignedInts toString vIntGu       System out println sIntGu      4294967295      long vLongGu   UnsignedLongs parseUnsignedLong  18446744073709551615        System out println vLongGu      -1     String sLongGu   UnsignedLongs toString vLongGu       System out println sLongGu      18446744073709551615               Integer - Max range      Signed  From -2 147 483 648 to 2 147 483 647  from - 2 31  to 2 31     1      Unsigned  From 0 to 4 294 967 295 which equals 2 32 - 1       Long - Max range      Signed  From -9 223 372 036 854 775 808 to 9 223 372 036 854 775 807  from - 2 63  to 2 63 - 1      Unsigned  From 0 to 18 446 744 073 709 551 615 which equals 2 64     1

[java] How to use the unsigned Integer in Java 8 and Java 9?

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