While trying to run unit tests of Apache POI with JDK 19 and 20 eary access builds, we found a small difference in handling of very small "double" numbers.

This may be intentional, but I could not find any mentioning in the release notes of changes in this area.

How to reproduce:

The following unit-test works in JDKs up to 18, but fails in latest JDK 19 and JDK 20 early access builds.

Reproducing code-snippet:

        assertEquals("1.0E-323",
                Double.toString(0.00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001d));

Failure:


org.opentest4j.AssertionFailedError:
Expected :1.0E-323
Actual :9.9E-324