Pojo Model

public class Model {
    private String firstName;
    private String lastName;
    private int age;
    /* Getters and setters not shown for brevity */        
}

Example: String to Object

Model outputObject = objectMapper.readValue(
     "{\\"firstName\\":\\"John\\",\\"lastName\\":\\"Doe\\",\\"age\\":23}",
     Model.class);
System.out.println(outputObject.getFirstName());
//result: John

Example: Object to String

String jsonString = objectMapper.writeValueAsString(inputObject));
//result: {"firstName":"John","lastName":"Doe","age":23}

Details

Import statement needed:

import com.fasterxml.jackson.databind.ObjectMapper;

Maven dependency: jackson-databind

ObjectMapper instance

//creating one
ObjectMapper objectMapper = new ObjectMapper();

Deserialization:

<T> T readValue(String content, Class<T> valueType)