org.springframework.http.converter.HttpMessageNotReadableException: Could not read JSON document: Unexpected character

Question

We are getting the below error message when trying to read content that has href tag and results in bad request.

15:08:57.712 [ajp-nio-9014-exec-1] DEBUG o.s.c.a.ClassPathScanningCandidateComponentProvider - Identified candidate component class: URL [jar:file:/u01/websites/gbk/WEB-INF/lib/dxa-data-model-2.0.0.jar!/com/sdl/dxa/api/datamodel/model/util/ListWrapper$RichTextDataListWrapper.class] 15:08:57.746 [ajp-nio-9014-exec-1] DEBUG o.s.web.client.RestTemplate - Setting request Accept header to [application/json, application/*+json] 15:08:59.668 [ajp-nio-9014-exec-1] DEBUG o.s.web.client.RestTemplate - GET request for "http://10.40.6.23:8998/ModelService/PageModel/tcm/27//en/about-us/contact-us?includes=INCLUDE" resulted in 200 (null) 15:08:59.670 [ajp-nio-9014-exec-1] DEBUG o.s.web.client.RestTemplate - Reading [class com.sdl.dxa.api.datamodel.model.PageModelData] as "application/json;charset=UTF-8" using [org.springframework.http.converter.json.MappingJackson2HttpMessageConverter@61a760aa] 15:08:59.707 [ajp-nio-9014-exec-1] DEBUG c.s.d.a.d.j.ModelDataTypeIdResolver - Found id = List`1 which we don't know, create a content holder to just save the data 15:08:59.713 [ajp-nio-9014-exec-1] DEBUG o.s.w.s.m.m.a.ExceptionHandlerExceptionResolver - Resolving exception from handler [public java.lang.String com.sdl.dxa.modules.generic.controller.GenericPageController.handleGetPage(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse) throws java.lang.Exception]: org.springframework.http.converter.HttpMessageNotReadableException: Could not read JSON document: Unexpected character ('m' (code 109)): was expecting comma to separate Array entries at [Source: (PushbackInputStream); line: 1, column: 4049] at [Source: (PushbackInputStream); line: 1, column: 4024] (through reference chain: com.sdl.dxa.api.datamodel.model.PageModelData["Regions"]->java.util.ArrayList[1]->com.sdl.dxa.api.datamodel.model.RegionModelData["Entities"]->java.util.ArrayList[0]->com.sdl.dxa.api.datamodel.model.EntityModelData["Content"]); nested exception is com.fasterxml.jackson.databind.JsonMappingException: Unexpected character ('m' (code 109)): was expecting comma to separate Array entries at [Source: (PushbackInputStream); line: 1, column: 4049] at [Source: (PushbackInputStream); line: 1, column: 4024] (through reference chain: com.sdl.dxa.api.datamodel.model.PageModelData["Regions"]->java.util.ArrayList[1]->com.sdl.dxa.api.datamodel.model.RegionModelData["Entities"]->java.util.ArrayList[0]->com.sdl.dxa.api.datamodel.model.EntityModelData["Content"]) 15:08:59.714 [ajp-nio-9014-exec-1] DEBUG o.s.w.s.m.a.ResponseStatusExceptionResolver - Resolving exception from handler [public java.lang.String com.sdl.dxa.modules.generic.controller.GenericPageController.handleGetPage(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse) throws java.lang.Exception]: org.springframework.http.converter.HttpMessageNotReadableException: Could not read JSON document: Unexpected character ('m' (code 109)): was expecting comma to separate Array entries at [Source: (PushbackInputStream); line: 1, column: 4049] at [Source: (PushbackInputStream); line: 1, column: 4024] (through reference chain: com.sdl.dxa.api.datamodel.model.PageModelData["Regions"]->java.util.ArrayList[1]->com.sdl.dxa.api.datamodel.model.RegionModelData["Entities"]->java.util.ArrayList[0]->com.sdl.dxa.api.datamodel.model.EntityModelData["Content"]); nested exception is com.fasterxml.jackson.databind.JsonMappingException: Unexpected character ('m' (code 109)): was expecting comma to separate Array entries at [Source: (PushbackInputStream); line: 1, column: 4049] at [Source: (PushbackInputStream); line: 1, column: 4024] (through reference chain: com.sdl.dxa.api.datamodel.model.PageModelData["Regions"]->java.util.ArrayList[1]->com.sdl.dxa.api.datamodel.model.RegionModelData["Entities"]->java.util.ArrayList[0]->com.sdl.dxa.api.datamodel.model.EntityModelData["Content"])

One of the components' preview looks like this

"fullContent": {
      "$type": "ContentModelData",
      "paraContent": {
        "$type": "List`1",
        "$values": [
          {
            "Fragments": [
              "Email us<span><a href=\"mailto:[email protected]\" target=\"_blank\">[email protected]</a></span>"
            ]
          },
          {
            "Fragments": [
              "Telephone<span><a href=\"tel:+0123456789\">+01234567890</a></span>"
            ]
          },
          {
            "Fragments": [
              "Mailing Address<span>Address Line 1,P.O. Box, Queens 12, Kuwait</span>"
            ]
          }
        ]
      }
    }
  },

Answer 1

OK, the JSON fragment reveals the problem: the "$type": "List``1" is not expected (it should be "$type": "RichTextData[]"); you can see that in the exception message: "ModelDataTypeIdResolver - Found id = List`1 which we don't know".

This is an issue in the DXA 2.0 TBBs, which seems to have been fixed in code already: https://github.com/sdl/dxa-content-management/commit/a2c209d63a0685e74d2015fa83d8b30d1befc64c

This is a kind of hotfix on the DXA 2.0 TBBs, but a DXA 2.0.1 hotfix release has not been created, so you will have to build the TBBs yourself from code to get this fixed. Alternatively, you can contact SDL Support to see if you can get this hotfix.