Elasticsearch Java API addMapping() usage

Problem: How to create a mapping with java from a json file

I don't want to use XContentBuilder as the json comes from a file!

I have the following json file to create my mapping from:

Using Sense with PUT /indexname it does create an index from it.

{
  "mappings": {
    "de_brochures": {
      "properties": {
        "text": {
          "type": "string",
          "store": true,
          "index_analyzer": "de_analyzer"
        },
        "classification": {
          "type": "string",
          "index": "not_analyzed"
        },
        "language": {
          "type": "string",
          "index": "not_analyzed"
        }
      }
    },
    "en_brochures": {
      "properties": {
        "text": {
          "type": "string",
          "store": true,
          "index_analyzer": "en_analyzer",
          "term_vector": "yes"
        },
        "classification": {
          "type": "string",
          "index": "not_analyzed"
        },
        "language": {
          "type": "string",
          "index": "not_analyzed"
        }
      }
    }
  },
  "settings": {
    "analysis": {
      "filter": {
        "de_stopwords": {
          "type": "stop",
          "stopwords": "_german_"
        },
        "de_stemmer": {
          "type": "stemmer",
          "name": "light_german"
        },
        "en_stopwords": {
          "type": "stop",
          "stopwords": "_english_"
        },
        "en_stemmer": {
          "type": "stemmer",
          "name": "light_english"
        }
      },
      "analyzer": {
        "de_analyzer": {
          "type": "custom",
          "tokenizer": "standard",
          "filter": [
            "lowercase",
            "de_stopwords",
            "de_stemmer"
          ]
        },
        "en_analyzer": {
          "type": "custom",
          "tokenizer": "standard",
          "filter": [
            "lowercase",
            "en_stopwords",
            "en_stemmer"
          ]
        }
      }
    }
  }
}

I have tried this in java: (This is already my second attempt, where I splitted the json into two separate files. Just using addMapping did not work for me)

CreateIndexRequestBuilder createIndexRequestBuilder = client.admin().indices().prepareCreate(index);
// CREATE SETTINGS
String settings_json = new String(Files.readAllBytes(brochures_mapping_path));
createIndexRequestBuilder.setSettings(settings_json);
// CREATE MAPPING
String mapping_json = new String(Files.readAllBytes(brochures_mapping_path));
createIndexRequestBuilder.addMapping(type, mapping_json);
CreateIndexResponse indexResponse = createIndexRequestBuilder.execute().actionGet();

It fails with the error:

Caused by: org.elasticsearch.index.mapper.MapperParsingException:
Root type mapping not empty after parsing! Remaining fields:   [mappings : {en_brochures={properties={text={index_analyzer=en_analyzer, store=true, term_vector=yes, type=string}, classification={index=not_analyzed, type=string}, language={index=not_analyzed, type=string}}}, de_brochures={properties={text={index_analyzer=de_analyzer, store=true, type=string}, classification={index=not_analyzed, type=string}, language={index=not_analyzed, type=string}}}}]

Any help is welcome :)