What Json string should it be to send SNS (AWS) message for iOS with sound by AWS Java SDK?

I absolutely broke my head. I have code which send SNS (AWS) for iOS with line:

PublishRequest publishRequest = new PublishRequest("arn:aws:sns:us-east-1:my:topic", messageBody);

and it works fine when I pass there Json like this:

{"message": "ldjldkjlk"}

But of course I need sound to my notification and nothing is works for me. I tried with Json which works when I pass it to SNS GUI, something like that:

{"message": { 
    "default": "HERE IS AN ALERT, BADGE, and SOUND",
    "APNS_SANDBOX": "{\"aps\": {\"alert\":\"HERE IS AN ALERT, BADGE, and SOUND!\",\"badge\": 1,\"sound\":\"bingbong.aiff\"}}"
}}

But I get error:

{"timestamp":1435334944602,"status":400,"error":"Bad Request","exception":"org.springframework.http.converter.HttpMessageNotReadableException","message":"Could not read JSON: Can not deserialize instance of java.lang.String out of START_OBJECT token\n at [Source: java.io.PushbackInputStream@2db14d22; line: 1, column: 15]; nested exception is com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of java.lang.String out of START_OBJECT token\n at [Source: java.io.PushbackInputStream@2db14d22; line: 1, column: 15]","path":"/sns/send"}

What did they do with PublishRequest? What I should pass there? It will be amazing if somebody helps me!