#fixed code
                                @Test
    public void testMergeSelf_forceNormal() throws CardinalityMergeException, IOException {
        final int[] cardinalities = {0, 1, 10, 100, 1000, 10000, 100000, 1000000};
        for (int cardinality : cardinalities) {
            for (int j = 4; j < 24; j++) {
                System.out.println("p=" + j);
                HyperLogLogPlus hllPlus = new HyperLogLogPlus(j, 0);
                for (int l = 0; l < cardinality; l++) {
                    hllPlus.offer(Math.random());
                }
                System.out.println("hllcardinality=" + hllPlus.cardinality() + " cardinality=" + cardinality);
                HyperLogLogPlus deserialized = HyperLogLogPlus.Builder.build(hllPlus.getBytes());
                assertEquals(hllPlus.cardinality(), deserialized.cardinality());
                ICardinality merged = hllPlus.merge(deserialized);
                System.out.println(merged.cardinality() + " : " + hllPlus.cardinality());
                assertEquals(hllPlus.cardinality(), merged.cardinality());
                assertEquals(hllPlus.cardinality(), hllPlus.cardinality());
            }
        }
    }
#vulnerable code 
                                @Test
    public void testMergeSelf_forceNormal() throws CardinalityMergeException, IOException {
        final int[] cardinalities = {0, 1, 10, 100, 1000, 10000, 100000, 1000000};
        for (int cardinality : cardinalities) {
            for (int j = 4; j < 24; j++) {
                System.out.println("p=" + j);
                HyperLogLogPlus hllPlus = new HyperLogLogPlus(j, 0);
                for (int l = 0; l < cardinality; l++) {
                    hllPlus.offer(Math.random());
                }
                System.out.println("hllcardinality=" + hllPlus.cardinality() + " cardinality=" + cardinality);
                HyperLogLogPlus deserialized = HyperLogLogPlus.Builder.build(hllPlus.getBytes());
                assertEquals(hllPlus.cardinality(), deserialized.cardinality());
                ICardinality merged = hllPlus.merge(deserialized);
                System.out.println(merged.cardinality() + " : " + hllPlus.cardinality());
                assertEquals(hllPlus.cardinality(), merged.cardinality());
            }
        }
    } 
                            #location 9 
                            #vulnerability type NULL_DEREFERENCE