Flume ElasticSearch Sink not indexing JSON data

I am posting JSON data to ElasticSearch using Flume . But for some reason
it is not loading the correct data in the message. Instead of JSON message
it is storing message data as
"org.elasticsearch.common.xcontent.XContentBuilder [ at ] 32f4122e"

I tried using the DynamicSerializer which determines the content-type. But
no luck.

Here is the sample data posted on Elastic Search.

"_index": "test_flume-2014-04-07",

"_type": "logs",

"_id": "M9E-33RQTy2kA6QhW6mSUw",

"_score": null,

"_source": {

"@message": "org.elasticsearch.common.xcontent.XContentBuilder [ at ] 58bf76d2
",

"@timestamp": "2014-04-07T09:49:26.490Z",

"@fields": {

"timestamp": "1396864166490"

},

"sort": [

1396864166490,

1396864166490

org.elasticsearch.common.xcontent.XContentBuilder