Demo project to reproduce Data Rest JPA Bug

Build and start application

mvn spring-boot:start

To stop app run

mvn spring-boot:stop

Init script created database and necessary tables with data.

Open HAL explorer and perform POST request to the task resource with the next data:

{
  "number": 1,
  "author": "http://localhost:8080/users/1",
  "name": "Test"
}

Expected behaviour:

Spring Data REST converts author using URI to Entity object.

Actual behaviour:

Spring Data REST throws exception:

{
  "cause": {
    "cause": null,
    "message": "Cannot construct instance of `com.lagoshny.spring_data_rest_demo.db.User` (although at least one Creator exists): no String-argument constructor/factory method to deserialize from String value ('http://localhost:8080/users/1')\n at [Source: REDACTED (`StreamReadFeature.INCLUDE_SOURCE_IN_LOCATION` disabled); byte offset: #29] (through reference chain: com.lagoshny.spring_data_rest_demo.db.Task[\"author\"])"
  },
  "message": "JSON parse error: Cannot construct instance of `com.lagoshny.spring_data_rest_demo.db.User` (although at least one Creator exists): no String-argument constructor/factory method to deserialize from String value ('http://localhost:8080/users/1')"
}

How to fix

1. In Spring Boot 4 uncomment @Bean in com.lagoshny.spring_data_rest_demo.config.AppConfig file and restart app. Now Spring Data REST will use the right converter for hal request and author will be converted from URI to Entity object.

2. Downgrade Spring Boot to last 3.x.x version in pom.xml and restart application.