# Converting a FacetBuilder to Json

**URL:** <https://discuss.elastic.co/t/converting-a-facetbuilder-to-json/5484>\
**Category:** Elasticsearch\
**Created:** [September 30, 2011, 5:49am UTC](https://discuss.elastic.co/t/converting-a-facetbuilder-to-json/5484 "2011-09-30T05:49:44Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![leonm](https://avatars.discourse-cdn.com/v4/letter/l/a9adbd/32.png) [@leonm](https://discuss.elastic.co/u/leonm)\
**Post date:** [September 30, 2011, 5:49am UTC](https://discuss.elastic.co/t/converting-a-facetbuilder-to-json/5484/1 "2011-09-30T05:49:44Z")

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I'm trying to write a little Unit Test to check that we setting up our objects correctly. To do this I'm setting up a FacetBuilder and convert it to Json that from where I can assert its correctness.

However, when I try to convert the FacetBuilder to Json I get an Exception:

TermsFacetBuilder facetBuilder = FacetBuilders.termsFacet("name").field("field");  
String jsonString = facetBuilder.toXContent(XContentFactory.safeJsonBuilder(), EMPTY\_PARAMS).string();

org.elasticsearch.common.jackson.JsonGenerationException: Can not write a field name, expecting a value  
at org.elasticsearch.common.jackson.impl.JsonGeneratorBase.\_reportError(JsonGeneratorBase.java:480)  
at org.elasticsearch.common.jackson.impl.Utf8Generator.writeFieldName(Utf8Generator.java:270)  
at org.elasticsearch.common.xcontent.json.JsonXContentGenerator.writeFieldName(JsonXContentGenerator.java:70)  
at org.elasticsearch.common.xcontent.XContentBuilder.field(XContentBuilder.java:253)  
at org.elasticsearch.common.xcontent.XContentBuilder.startObject(XContentBuilder.java:139)  
at org.elasticsearch.search.facet.terms.TermsFacetBuilder.toXContent(TermsFacetBuilder.java:211)

I tried both versions 0.17.4 and 0.17.7 with pretty consistent results (StackTrace is for 0.17.7)

I fired up a debugger and stepped through the code and there is nothing that is null or otherwise broken.

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [July 6, 2017, 3:53am UTC](https://discuss.elastic.co/t/converting-a-facetbuilder-to-json/5484/2 "2017-07-06T03:53:17Z")

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