import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.math.BigInteger;
import java.util.Arrays;
import java.util.stream.Collectors;

@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
@interface DontSerialize
{
}

class CheckIt
{
	CheckIt() { X = 3; Y = 4; }
	CheckIt(int x, int y) { X = x; Y = y; }
	public int X;
	@DontSerialize public int Y;
}

public class Serializer {
	public static void serialize(Object o, OutputStream os) throws IOException, IllegalArgumentException, IllegalAccessException
	{
		ObjectOutputStream oos = new ObjectOutputStream(os);
		if (o.getClass() == BigInteger.class) {
			oos.writeObject(((BigInteger)o).toByteArray());
		//} else if (o.getClass().isPrimitive()) {
		} else {
			Field[] fs = Arrays.stream(o.getClass().getDeclaredFields()).filter((f) -> !f.isAnnotationPresent(DontSerialize.class)).collect(Collectors.toList()).toArray(new Field[]{});
			/*Field[] fs = o.getClass().getFields();
			int len = 0;
			for (Field f : fs) {
				if (!f.isAnnotationPresent(DontSerialize.class)) {
					len++;
				}
			}
			oos.writeInt(len);*/
			oos.writeInt(fs.length);
			for (Field f : fs) {
				//if (!f.isAnnotationPresent(DontSerialize.class)) {
					oos.writeObject(f.getName());
					boolean bacc = f.isAccessible();
					if (!bacc) f.setAccessible(true);
					oos.writeObject(f.get(o));
					if (!bacc) f.setAccessible(false);
				//}
			}
		}
	}
	public static Object deserialize(Class<?> c, InputStream is) throws IOException, ClassNotFoundException, InstantiationException, IllegalAccessException, NoSuchFieldException, SecurityException
	{
		ObjectInputStream ois = new ObjectInputStream(is);
		if (c == BigInteger.class) {
			return new BigInteger((byte[])ois.readObject());
		} else {
			Object o = c.newInstance();
			int len = ois.readInt();
			while (len != 0) {
				Field f = c.getDeclaredField((String)ois.readObject());
				boolean bacc = f.isAccessible();
				if (!bacc) f.setAccessible(true);
				if (!Modifier.isFinal(f.getModifiers())) f.set(o, ois.readObject());
				if (!bacc) f.setAccessible(false);
				len--;
			}
			return o;
		}
	}
	public static void main(String [] args) throws IllegalArgumentException, IllegalAccessException, IOException, ClassNotFoundException, InstantiationException, NoSuchFieldException, SecurityException
	{
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		serialize(new java.awt.Point(3, 4), baos);
		ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
		java.awt.Point p = (java.awt.Point)deserialize(java.awt.Point.class, bais);
		System.out.println(p.toString());

		baos.reset();
		serialize(new BigInteger("314159265359"), baos);
		bais = new ByteArrayInputStream(baos.toByteArray());
		BigInteger b = (BigInteger)deserialize(BigInteger.class, bais);
		System.out.println(b.toString());

		baos.reset();
		serialize(new CheckIt(1, 2), baos);
		bais = new ByteArrayInputStream(baos.toByteArray());
		CheckIt ci = (CheckIt)deserialize(CheckIt.class, bais);
		System.out.println(ci.X + " " + ci.Y);
	}
}