ADDITIONAL SYSTEM INFORMATION :
failed on all java 8, 11, and 17
tested only on windows 10.

A DESCRIPTION OF THE PROBLEM :
sometimes HashMap.putAll would cause the hashmap.table be double length than should be.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
for jdk 8-:
just run the tests I provided and see the results.
for jdk 9+:
make a break point before the System.out.println("a : " + getArrayLength(a));
then see values of a.table.length, b.table.length, c.table.length, d.table.length using debugger tool.


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
for jdk 8-:
the output should be
a : 16
b : 16
c : 16
d : 16
for jdk 9+:
a.table.length = 16
b.table.length = 16
c.table.length = 16
d.table.length = 16
ACTUAL -
for jdk 8-:
the output should be
a : 16
b : 16
c : 32
d : 32
for jdk 9+:
a.table.length = 16
b.table.length = 16
c.table.length = 32
d.table.length = 32

---------- BEGIN SOURCE ----------
import java.lang.reflect.Array;
import java.lang.reflect.Field;
import java.util.HashMap;
import java.util.Map;

public class TestMap {

    public static void main(String[] args) throws NoSuchFieldException, IllegalAccessException {
        HashMap<Object, Object> a = new HashMap<>();
        fill12(a);
        HashMap<Object, Object> b = new HashMap<>(12);
        fill12(b);
        HashMap<Object, Object> c = new HashMap<>(a);
        HashMap<Object, Object> d = new HashMap<>();
        d.putAll(a);
        System.out.println("a : " + getArrayLength(a));
        System.out.println("b : " + getArrayLength(b));
        System.out.println("c : " + getArrayLength(c));
        System.out.println("d : " + getArrayLength(d));
    }

    public static void fill12(Map<Object, Object> map) {
        for (int i = 0; i < 12; i++) {
            map.put(i, i);
        }
    }

    public static int getArrayLength(Map<Object, Object> map) throws NoSuchFieldException, IllegalAccessException {
        Field field = HashMap.class.getDeclaredField("table");
        field.setAccessible(true);
        Object table = field.get(map);
        return Array.getLength(table);
    }

}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
change the original calculation from (int) (expected / 0.75F + 1) to (int) Math.ceil(expected / 0.75)

FREQUENCY : always