Create Unsigned Long in Java

1. Create Unsigned Long Integer Using BigInteger in Java
2. Unsigned Long Using ULong of the jOOU

A long variable in Java is always signed, which always has negative and positive values. But we can also use and treat the general long variable as an unsigned variable using a few methods mentioned below.

Create Unsigned Long Integer Using BigInteger in Java

In Java, primitive types like long provide a vast range of big integer calculations.

Still, to go further than that range, we need to use the BigInteger class that we can use to perform mathematical operations on larger values than the primitive types can hold. As the unsigned long value is large, we use the BigInteger.

In this example, we first call the valueOf() function of the BigInteger class and pass Long.MAX_VALUE, the maximum value it can store. Then, we add the value that we want to store, which we get using BigInteger.valueOf() and pass the value.

To convert the BigInteger value to a long value we use BigInteger.longValue() and then we make the longValue as a Unsigned String by calling Long.toUnsignedString() and pass the longValue variable. We can see that the value is printed in the output, and it is a positive number which means that it is an unsigned long value.

import java.math.BigInteger;

public class UnsignedLongExample {
    public static void main(String[] args) {

        BigInteger bigInteger = BigInteger.valueOf(Long.MAX_VALUE)
                .add(BigInteger.valueOf(25634));

        long longValue = bigInteger.longValue();

        String longAsUnsignedString = Long.toUnsignedString(longValue);
        System.out.println(longAsUnsignedString);
    }
}

Output:

9223372036854801441

If we print the longValue directly, we get a negative value because long is still a signed variable but the function toUnsignedString() converts it to a string with the unsigned value.

System.out.println(longValue);

Output:

-9223372036854750175

Unsigned Long Using ULong of the jOOU

Another way to get and use an unsigned long value is by using a third-party library called jOOU. We need to import the following maven dependency to use it.

<dependency>
    <groupId>org.jooq</groupId>
    <artifactId>joou</artifactId>
    <version>0.9.4</version>
</dependency>

The ULong class in org.jooq.tools.unsigned provides a few methods to convert a long value to an unsigned value. One of the methods is the valueOf() method that takes a long value.

In the program, we create a BigInteger and then in the ULong.valueOf() method, we pass the long value using bigInteger.longValue() that returns a ULong object.

import org.jooq.tools.unsigned.ULong;

import java.math.BigInteger;

public class UnsignedLongExample {
    public static void main(String[] args) {

        BigInteger bigInteger = BigInteger.valueOf(Long.MAX_VALUE)
                .add(BigInteger.valueOf(25634));

        ULong uLong = ULong.valueOf(bigInteger.longValue());
        System.out.println(uLong);
    }
}

Output:

9223372036854801441