Duplicate HttpMessageConverter after calling org.springframework.boot.autoconfigure.http.HttpMessageConverters#getCombinedConverters method

https://github.com/spring-projects/spring-boot/blob/5282d4e0f2/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/http/HttpMessageConverters.java#L118-L138

converters 1. org.springframework.http.converter.StringHttpMessageConverter 2. org.springframework.http.converter.xml.MappingJackson2XmlHttpMessageConverter 3. org.springframework.http.converter.json.MappingJackson2HttpMessageConverter

defaultConverters 1. org.springframework.http.converter.ByteArrayHttpMessageConverter 2. org.springframework.http.converter.StringHttpMessageConverter 3. org.springframework.http.converter.ResourceHttpMessageConverter 4. org.springframework.http.converter.xml.SourceHttpMessageConverter 5. org.springframework.http.converter.json.MappingJackson2HttpMessageConverter 6. org.springframework.http.converter.xml.MappingJackson2XmlHttpMessageConverter

combined 1. org.springframework.http.converter.ByteArrayHttpMessageConverter 2. org.springframework.http.converter.StringHttpMessageConverter 3. org.springframework.http.converter.StringHttpMessageConverter 4. org.springframework.http.converter.ResourceHttpMessageConverter 5. org.springframework.http.converter.xml.SourceHttpMessageConverter 6. org.springframework.http.converter.json.MappingJackson2HttpMessageConverter 7. org.springframework.http.converter.json.MappingJackson2HttpMessageConverter 8. org.springframework.http.converter.xml.MappingJackson2XmlHttpMessageConverter 9. org.springframework.http.converter.xml.MappingJackson2XmlHttpMessageConverter

The following is repeated: 3. org.springframework.http.converter.StringHttpMessageConverter 7. org.springframework.http.converter.json.MappingJackson2HttpMessageConverter 9. org.springframework.http.converter.xml.MappingJackson2XmlHttpMessageConverter

Comment From: wilkinsona

@brucelwl Please take a moment to search for existing issues. This is a duplicate of #21374 which you raised a couple of years ago. It has also been covered more recently in https://github.com/spring-projects/spring-boot/issues/27319, for example.