[Solved] Why does this code throw an exception?ObjectMapper mapper = new ObjectMapper();String json = "{\"name\":\"Eve\", \"age\":28}";User user = mapper.readValue(json, User.... | Spring Boot

Spring Boot - Request and Response Handling

Why does this code throw an exception?

ObjectMapper mapper = new ObjectMapper();
String json = "{\"name\":\"Eve\", \"age\":28}";
User user = mapper.readValue(json, User.class);

Given User class:

public class User {
  private String name;
  private int age;
}

APrivate fields without setters cause deserialization failure

BJSON string format is invalid

CNo default constructor in User class

DObjectMapper cannot parse strings

Step-by-Step Solution

Solution:

Step 1: Understand deserialization requirements
Jackson needs setters or public fields to set values during deserialization.
Step 2: Identify missing setters for private fields
Private fields without setters cause Jackson to fail setting values, throwing exception.
Final Answer:
Private fields without setters cause deserialization failure -> Option A
Quick Check:
Deserialization needs setters for private fields [OK]

Quick Trick: Add setters for private fields to enable deserialization [OK]

Common Mistakes:

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Why does this code throw an exception?