[FIXED] How to use records for @ConfigurationProperties in Spring Boot 2.6.4 (class may not be final)

Issue

I have a pretty vanilla Spring Boot v2.6.4 Java application, using Java 17.

I am trying to get records to work for my @ConfigurationProperties, but having little success.

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.context.properties.ConstructorBinding;
import org.springframework.context.annotation.Configuration;

@Configuration
@ConfigurationProperties(prefix = "custom")
@ConstructorBinding
public record CustomConfigProperties(String path) { }

This fails with: org.springframework.beans.factory.parsing.BeanDefinitionParsingException: Configuration problem: @Configuration class 'CustomConfigProperties' may not be final. Remove the final modifier to continue.

Obviously, records are implicitly final, so I am stumped. No amount of googling yields anything useful. The closest I could find was this SO question, but it's not really directly related Infact a commenter on there has the same issue as me)

Solution

@Configuration should be used on a class that defines beans via @Bean methods. Annotating with @Configuration triggers the creation of a CGLib proxy to intercept calls between these @Bean methods. It is this proxying attempt that is failing because the record is implicitly final.

You should remove @Configuration from your record and then enable your @ConfigurationProperties record using @ConfigurationPropertiesScan or @EnableConfigurationProperties(CustomConfigProperties.class). You can also remove @ConstructorBinding as records are implicitly constructor bound. @ConstructorBinding need only be used on a record if the record has multiple constructors and you need to indicate which constructor should be used for property binding.

Answered By - Andy Wilkinson
Answer Checked By - Mildred Charles (JavaFixing Admin)