ADDITIONAL SYSTEM INFORMATION :
Windows 11 21H2
openjdk version "17.0.6" 2023-01-17
OpenJDK Runtime Environment Temurin-17.0.6+10 (build 17.0.6+10)
OpenJDK 64-Bit Server VM Temurin-17.0.6+10 (build 17.0.6+10, mixed mode, sharing)

A DESCRIPTION OF THE PROBLEM :
L32X64MixRandom#NextLong() is implemented like this:

```
return ((long)nextInt() << 32) ^ (long)nextInt();
```

I think it's meant to simply concatenate two words.
But `(long)nextInt()` does sign extension; if the most significant bit is 1, the upper 32 bits will be inverted.
(e.g. When `nextInt()` returns 0xfedcba98, `(long)nextInt()` will be 0xfffffffffedcba98, instead of 0xfedcba98.)

Because of this problem, the output of random numbers is different than originally intended.


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Please run the code attached to the test case.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The first line (nextInt) looks like this:
2a162bd60afba596 b78c76a4f8b54e56 d225cfec3c126b35 743cdf79f289f5a4
ACTUAL -
The second line (nextLong) looks like this:
2a162bd60afba596 4873895bf8b54e56 d225cfec3c126b35 8bc32086f289f5a4

The upper 32 bits of the second and fourth results are inverted.

---------- BEGIN SOURCE ----------
import java.util.random.*;

class javaprng {
    public static void main(String[] args) {
        // expected
        RandomGenerator rng = RandomGeneratorFactory.of("L32X64MixRandom").create(42);
        for (int i = 0; i < 4; i++) {
            System.out.printf("%08x%08x ", rng.nextInt(), rng.nextInt());
        }

        System.out.println();

        // actual
        rng = RandomGeneratorFactory.of("L32X64MixRandom").create(42);
        for (int i = 0; i < 4; i++) {
            System.out.printf("%016x ", rng.nextLong());
        }
    }
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
https://github.com/openjdk/jdk/blob/c313e1ac7b3305b1c012755de4e94728b17e2505/src/jdk.random/share/classes/jdk/random/L32X64MixRandom.java#L255

Change this line to:
        return ((long)nextInt() << 32) ^ Integer.toUnsignedLong(nextInt());

But I am also concerned that this change will damage the reproducibility of random numbers.

FREQUENCY : always