HttpUriRequest e HttpPut, enviando uma string de carga útil com caracteres multilíngues.

/*
 * A Java String doesn't have an encoding but it can easily be forced into UTF-16 on conversions. 
 * ALWAYS specify UTF-8 when creating a new StringEntity from String!
 */
// Add payload to HttpPut
HttpPut hp = (HttpPut) this.request;
hp.setEntity(new StringEntity(yourStringPayload, "UTF-8"));
hp.setHeader("Content-Type", "application/json");
// ... then execute