# HttpMessageNotReadableException: JSON parse error / Required request body is missing

**Code:** `HttpMessageNotReadableException` · **Category:** Java · **Seen on:** Java

Spring couldn’t read the request body into your @RequestBody object.

## Meaning

Malformed JSON, wrong types for fields, a missing body, or sending form data to a JSON endpoint.

## Common causes

- Invalid JSON
- Field type mismatch (string vs number, date format)
- Empty body on @RequestBody
- Wrong Content-Type

## Quick fix

1. Validate the JSON payload
2. Match field types and date formats
3. Send Content-Type: application/json
4. Make @RequestBody(required = false) if optional

## Detailed fix by platform

### Java

1. Return 400 with the parse message via @ExceptionHandler(HttpMessageNotReadableException.class)

## How to diagnose

1. **Body** — Is it valid JSON?
2. **Types** — Which field fails?

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Source: [WhatIsMyError](https://whatismyerror.com/errors/java/spring-httpmessagenotreadableexception)