For the sake of the example lets assume you have a class Person with just a name.

private class Person {
    public String name;

    public Person(String name) {
        this.name = name;
    }
}

Jackson (Maven)

My personal favourite and probably the most widely used.

ObjectMapper mapper = new ObjectMapper();

// De-serialize to an object
Person user = mapper.readValue("{\"name\": \"John\"}", Person.class);
System.out.println(user.name); //John

// Read a single attribute
JsonNode nameNode = mapper.readTree("{\"name\": \"John\"}");
System.out.println(nameNode.get("name").asText());

Google GSON (Maven)

Gson g = new Gson();

// De-serialize to an object
Person person = g.fromJson("{\"name\": \"John\"}", Person.class);
System.out.println(person.name); //John

// Read a single attribute
JsonObject jsonObject = new JsonParser().parseString("{\"name\": \"John\"}").getAsJsonObject();
System.out.println(jsonObject.get("name").getAsString()); //John

Org.JSON (Maven)

This suggestion is listed here simply because it appears to be quite popular due to stackoverflow reference to it. I would not recommend using it as it is more a proof-of-concept project than an actual library.

JSONObject obj = new JSONObject("{\"name\": \"John\"}");

System.out.println(obj.getString("name")); //John

Yes Using Json parser you can parse your Json, Below is a sample example you can find more in jackson documentation

     JsonParser jsonParser = new JsonFactory().createJsonParser(jsonStr);
     while(jsonParser.nextToken() != JsonToken.END_OBJECT){
         String name = jsonParser.getCurrentName();
         if("name".equals(name)) {
             jsonParser.nextToken();
             System.out.println(jsonParser.getText());
         }
         if("surname".equals(name)) {
             jsonParser.nextToken();
             System.out.println(jsonParser.getText());
         }
         if("city".equals(name)) {
             jsonParser.nextToken();
             System.out.println(jsonParser.getText());
         }
     }

The gson api is better and its extremely simple to use.