"Projection type must be an interface"

[kopax]

I have tried to create Projection and exclude some field but I have the following error :

"Projection type must be an interface" 

Could this be related to spring-data-mybatis ?

[easybest]

can you show me your test case code?

[kopax]

I have created a repo https://github.com/kopax/spring-data-mybatis-testing

You need to checkout the "projection" branch

$ git clone git@github.com:kopax/spring-data-mybatis-testing.git
$ git checkout projection
$ ./gradlew build --info && java -jar build/libs/spring-data-mybatis-testing-0.1.0.war
$ curl http://localhost:8080/siteContents
{"timestamp":1486030282864,"status":500,"error":"Internal Server Error","exception":"org.springframework.http.converter.HttpMessageNotWritableException","message":"Could not write content: Projection type must be an interface! (through reference chain: org.springframework.hateoas.Resources[\"_embedded\"]->java.util.Collections$UnmodifiableMap[\"siteContents\"]->java.util.ArrayList[0]->org.springframework.data.rest.webmvc.json.PersistentEntityJackson2Module$ProjectionResource[\"content\"]->com.sun.proxy.$Proxy118[\"siteFunction\"]); nested exception is com.fasterxml.jackson.databind.JsonMappingException: Projection type must be an interface! (through reference chain: org.springframework.hateoas.Resources[\"_embedded\"]->java.util.Collections$UnmodifiableMap[\"siteContents\"]->java.util.ArrayList[0]->org.springframework.data.rest.webmvc.json.PersistentEntityJackson2Module$ProjectionResource[\"content\"]->com.sun.proxy.$Proxy118[\"siteFunction\"])","path":"/siteContents"}

I was not able to load the context to query my endpoints this is why I wasn't able to provide a sscce.org

[easybest]

also see:
https://github.com/hatunet/spring-data-mybatis-testing/tree/extendxml

[kopax]

I have tested in my project where I have a more complex object structure, The error is still the same :

I have updated the test case on branch extendxml

$ git clone git@github.com:kopax/spring-data-mybatis-testing.git
$ git checkout projection
$ ./gradlew build --info && java -jar build/libs/spring-data-mybatis-testing-0.1.0.war
$ curl http://localhost:8080/siteServices

Expect

HTTP 200

Result

2017-02-02 23:41:46.665  WARN 10352 --- [nio-8080-exec-1] .w.s.m.s.DefaultHandlerExceptionResolver : Failed to write HTTP message: org.springframework.http.converter.HttpMessageNotWritableException: Could not write content: Projection type must be an interface! (through reference chain: org.springframework.hateoas.Resources["_embedded"]->java.util.Collections$UnmodifiableMap["siteServices"]->java.util.ArrayList[0]->org.springframework.data.rest.webmvc.json.PersistentEntityJackson2Module$ProjectionResource["content"]->com.sun.proxy.$Proxy102["translateMessage"]); nested exception is com.fasterxml.jackson.databind.JsonMappingException: Projection type must be an interface! (through reference chain: org.springframework.hateoas.Resources["_embedded"]->java.util.Collections$UnmodifiableMap["siteServices"]->java.util.ArrayList[0]->org.springframework.data.rest.webmvc.json.PersistentEntityJackson2Module$ProjectionResource["content"]->com.sun.proxy.$Proxy102["translateMessage"])

I am using an interface TranslateMessageInterface for creating "translateMessage" which allow me to keep the logic of it in I18nId.java

It appeart that this line is an issue for the projection