Undesrtanding Java Serialization

问题

I'm trying to compare the standard Java desiralisation. And have a question if it's a correct way to do this. I wrote the following class:

//{"first", 1234.1234, 21341234, 234123412341234124L, "fifth"}
public class ArrayInputStreamStub extends InputStream{
    public int[] arr = new int[260];
    private int reader = 0;

    public ArrayInputStreamStub(){
        reader[0] = -84;
        //...
    }

    @Override
    public int read() throws IOException {
        return arr[reader++];
    }

    public void reset() {
        reader = 0;
    }
}

I have the same stub for HashMap.

//{("first", 1), ("second", 2), ("third", 3), ("fourth", 4), ("fifth", 5)}
public class HashMapInputStreamStub extends InputStream{
    //...
}

Now my benchmarks look as this:

public InputStreamStub is;
public ArrayInputStreamStub ais;

@Setup
public void setup(){
    is = new InputStreamStub();
    ais = new ArrayInputStreamStub();
}

@Benchmark
@OutputTimeUnit(TimeUnit.MICROSECONDS)
@BenchmarkMode(Mode.AverageTime)
public void measureDeserializeHashMap(Blackhole bh){
    try {
        ObjectInputStream ois = new ObjectInputStream(is);
        Map<String, Integer> schema = (Map<String, Integer>) ois.readObject();
        is.reset();
        bh.consume(schema);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

@Benchmark
@OutputTimeUnit(TimeUnit.MICROSECONDS)
@BenchmarkMode(Mode.AverageTime)
public void measureDeserializeArray(Blackhole bh){
    try {
        ObjectInputStream ois = new ObjectInputStream(ais);
        Object[] array = (Object[]) ois.readObject();
        ais.reset();
        bh.consume(array);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

The result I got is the following:

Benchmark                              Mode  Cnt   Score   Error  Units
MyBenchmark.measureDeserializeArray    avgt    5  15.940 ± 0.044  us/op
MyBenchmark.measureDeserializeHashMap  avgt    5  12.118 ± 0.057  us/op

Just ~10 microseconds for the following. I ran -prof gc, the result pretty much the same.

The question is about is that measurement correct? Serialization of these simple objects is ~10 microseconds?

来源：https://stackoverflow.com/questions/46959119/undesrtanding-java-serialization

标签

java

serialization

jmh