import com.fasterxml.jackson.databind.ObjectMapper;

import java.io.IOException;

public class Hello {

    public static void main(String args[]) throws IOException {
        Person p = new Person();
        p.age = 1;
        p.name = "Econ";

        ObjectMapper mapper = new ObjectMapper();
        String json = mapper.writeValueAsString(p);
        System.out.println(json);
//        {"age":1,"name":"Econ"}
        Person p2 = mapper.readValue(json, Person.class);
        System.out.println(p2);
//        Person.age=1, Person.name=Econ
    }
}

class Person {
    public int age;
    public String name;

    @Override
    public String toString() {
        return String.format("Person.age=%d, Person.name=%s", age, name);
    }
}

JAVA_LANG_OBJECT
OBJECT_AND_NON_CONCRETE
NON_CONCRETE_AND_ARRAYS
NON_FINAL

import com.fasterxml.jackson.databind.ObjectMapper;

import java.io.IOException;

public class Hello {

    public static void main(String args[]) throws IOException {
        Person p = new Person();
        p.age = 1;
        p.name = "Econ";
        p.object = new Dna();

        ObjectMapper mapper = new ObjectMapper();
        mapper.enableDefaultTyping(ObjectMapper.DefaultTyping.JAVA_LANG_OBJECT);
        String json = mapper.writeValueAsString(p);
        System.out.println(json);
//        {"age":1,"name":"Econ","object":["Dna",{"length":1}]}
        Person p2 = mapper.readValue(json, Person.class);
        System.out.println(p2);
//        Person.age=1, Person.name=Econ
    }
}

class Person {
    public int age;
    public String name;
    public Object object;

    @Override
    public String toString() {

        return String.format("Person.age=%d, Person.name=%s", age, name, object == null ? "null" : object);
    }
}

class Dna {
    public int length = 1;
        }

import com.fasterxml.jackson.databind.ObjectMapper;

import java.io.IOException;

public class Hello {

    public static void main(String args[]) throws IOException {
        Jacksonunserialize();

    }

    public static void Jacksonunserialize() throws IOException {
        String json = "{\"age\":1, \"name\":\"econ\"}";
        ObjectMapper mapper = new ObjectMapper();
        mapper.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_CONCRETE_AND_ARRAYS);
        Person person = mapper.readValue(json, Person.class);
        System.out.println(person);
        //  Person.age=1, Person.name=econ
    }
}

class Person {
    public int age;
    public String name;

    @Override
    public String toString() {

        return String.format("Person.age=%d, Person.name=%s", age, name);
    }
}

1.NativeConstructorAccessorImpl (sun.reflect)

class Dna {
    String cmd;

    Dna() {
        System.out.println("Dna.init()");
    }

    public void setCmd(String cmd) throws IOException {
        this.cmd = "calc.exe";
        System.out.println(String.format("Dna.setCmd(%s)", cmd));
        Runtime.getRuntime().exec(cmd);
    }
}