How to use BigInteger class to implement an unsigned 64 bit int in Java?

I'm looking for a data type with an exact capacity of 0 to 2 ^ 64 – 1 We know that Java does not support 'unsigned' restricted character data types

The BigInteger class allows you to create large numbers that cannot be supported by long data types But I don't know how the BigInteger class will serve my purpose The BigInteger class only allows allocation through constructors I see the following possibilities, but it will generate a random number

BigInteger(int numBits,Random rnd) 
Constructs a randomly generated BigInteger,uniformly distributed over the range 0 to (2^numBits - 1),inclusive.

I can't see any setValue (x) API, so I can choose my own value to this BigInteger How do you use the BigInteger class to achieve this, or are there other methods? Please mail a code example

PS: someone here released a problem without implementation details

Solution

You can often use Java's signed digital data types as if they were unsigned

See the old answer about Java signature and unsigned