spring-boot-crud | Spring Boot CRUD Example | DB Client library

Your url synax is faulty, the right option according to Thymeleaf documention for adding parameters is:

As it says you, The object User user that comes to the method is null, or one of its field is null. Make sure that this objects contains all data coming from view. Check also if all the field in your html file are well mapped to the field of the User object.

Problem not related to JPA after all. The problem is how you use th:field. See documentation about correct usage: https://www.thymeleaf.org/doc/tutorials/2.1/thymeleafspring.html#dynamic-fields

Try this:

You do not necessarily need to send the entire Account object, and you should be able to name your endpoints whatever you like, as long as they stem from the same base URL; it all depends on how you have your services and POJOS configured.

For instance, using JAX-RS, you can annotate a service class with @Path("path/you/want/here") to specify a base path for all methods accessible in that service, followed by more specific @Path annotations for each method to give them unique paths (the method level @Path annotation gets added to the end of the class level one). You can annotate your public methods with HTTP verb annotations like @GET or @POST to specify which verb that method will take.

In your REST endpoint methods, you can deserialize the incoming JSON into POJOs using Jackson, going as far as to specify which attributes are required, how they should be deserialized/serialized, and so on. As long as you don't need the attributes or you are expecting them to not always be there, you can simply allow missing POJO fields to deserialize to null.