Let's consider following code:

import java.util.IntSummaryStatistics;

public class IntSummStatsTest {
    public static void main(String[] asrt) {
        new IntSummaryStatistics().toString();
    }
}

Its running causes following output:

Exception in thread "main" java.util.IllegalFormatConversionException: d != java.lang.Double
at java.util.Formatter$FormatSpecifier.failConversion(Formatter.java:4309)
at java.util.Formatter$FormatSpecifier.printInteger(Formatter.java:2774)
at java.util.Formatter$FormatSpecifier.print(Formatter.java:2728)
at java.util.Formatter.format(Formatter.java:2514)
at java.util.Formatter.format(Formatter.java:2449)
at java.lang.String.format(String.java:2907)
at java.util.IntSummaryStatistics.toString(IntSummaryStatistics.java:154)
at IntSummStatsTest.main(IntSummStatsTest.java:5)

The same thing happens to LongStreamStatistics:

import java.util.LongSummaryStatistics;

public class LongSummStatsTest {
    public static void main(String[] asrt) {
        new LongSummaryStatistics().toString();
    }
}

the code above leads to:

Exception in thread "main" java.util.IllegalFormatConversionException: d != java.lang.Double
at java.util.Formatter$FormatSpecifier.failConversion(Formatter.java:4309)
at java.util.Formatter$FormatSpecifier.printInteger(Formatter.java:2774)
at java.util.Formatter$FormatSpecifier.print(Formatter.java:2728)
at java.util.Formatter.format(Formatter.java:2514)
at java.util.Formatter.format(Formatter.java:2449)
at java.lang.String.format(String.java:2907)
at java.util.LongSummaryStatistics.toString(LongSummaryStatistics.java:166)
at LongSummStatsTest.main(LongSummStatsTest.java:5)

The code is attached for your convenience.