using ReflectionToStringBuilder.toString on the "HashSet"

when using ReflectionToStringBuilder.toString on the HashSet<String>  it just throw an (java.lang.reflect.InaccessibleObjectException: Unable to make field private static final java.lang.Object java.util.HashSet.PRESENT accessible: module java.base does not "opens java.util" to unnamed module @37f8bb67)

the test code is
@Test public void testReflectionHierarchyHashSet() {
HashSet<String> set = new HashSet<>(); set.add("element1"); set.add("element2"); String result = ReflectionToStringBuilder.toString(set); assertNotNull("Result should not be null", result); assertTrue("Result should contain elements from the HashSet", result.contains("element1") && result.contains("element2")); {color}}
}

The test environment is jdk18