HotSpot boxing, Ceylon, anomaly

run.ceylon

import java.lang { System { o=\iout, nanoTime }, Double, Long }

Integer additions = 10_000_000_000;
String format = "%04d. iteration, %8s: %04.1f seconds (%12d ns): %d\n";
Float seconds(Integer t1, Integer t2) => (t2 - t1) / 1.0e9;
Integer nanos(Integer t1, Integer t2) => t2 - t1;

class C() {
    @unboxed variable Integer i1 = 0;
    @boxed variable Integer i2 = 0;

    shared void addU(@unboxed Integer i) {
        i1 += i;
    }
    shared void addB(@boxed Integer i) {
        i2 += i;
    }
    shared [Integer, Integer] result => [i1, i2];
}

shared void run() {
    for (iteration in 0:10) {
        value c = C();
        value t3 = nanoTime();
        for (x in 0:additions) {
            c.addB(x);
        }
        value t4 = nanoTime();
        o.printf(format, Long(iteration), "boxed", Double(seconds(t3, t4)), Long(nanos(t3, t4)), Long(c.result[1]));
        value t1 = nanoTime();
        for (x in 0:additions) {
            c.addU(x);
        }
        value t2 = nanoTime();
        o.printf(format, Long(iteration), "unboxed", Double(seconds(t1, t2)), Long(nanos(t1, t2)), Long(c.result[0]));
    }
}