Program: 93443
Project: 93443
Buggy source:
/** 
 * @param exchange
 * @param context
 * @throws Exception
 */
@Override public void handleRequest(HttpServerExchange exchange,RequestContext context) throws Exception {
  BsonValue responseContent=context.getResponseContent();
  if (context.getWarnings() != null && !context.getWarnings().isEmpty()) {
    if (responseContent == null) {
      responseContent=new BsonDocument();
    }
    BsonArray warnings=new BsonArray();
    if (responseContent.isDocument()) {
      if (context.getRepresentationFormat() == RequestContext.REPRESENTATION_FORMAT.PJ || context.getRepresentationFormat() == RequestContext.REPRESENTATION_FORMAT.PLAIN_JSON) {
        context.setResponseContentType(Representation.JSON_MEDIA_TYPE);
        responseContent.asDocument().append("String_Node_Str",warnings);
        context.getWarnings().forEach(w -> warnings.add(new BsonString(w)));
      }
 else {
        context.setResponseContentType(Representation.HAL_JSON_MEDIA_TYPE);
        BsonDocument _embedded;
        if (responseContent.asDocument().get("String_Node_Str") == null) {
          _embedded=new BsonDocument();
          responseContent.asDocument().append("String_Node_Str",_embedded);
        }
 else {
          _embedded=responseContent.asDocument().get("String_Node_Str").asDocument();
        }
        _embedded.append("String_Node_Str",warnings);
        context.getWarnings().forEach(w -> warnings.add(getWarningDoc(w)));
      }
    }
  }
  if (context.getRepresentationFormat() == RequestContext.REPRESENTATION_FORMAT.HAL) {
    exchange.getResponseHeaders().put(Headers.CONTENT_TYPE,Representation.HAL_JSON_MEDIA_TYPE);
  }
 else {
    exchange.getResponseHeaders().put(Headers.CONTENT_TYPE,Representation.JSON_MEDIA_TYPE);
  }
  exchange.setStatusCode(context.getResponseStatusCode());
  if (responseContent != null) {
    exchange.getResponseSender().send(JsonUtils.toJson(responseContent));
  }
  exchange.endExchange();
  next(exchange,context);
}

Fixed version (ground truth):
/** 
 * @param exchange
 * @param context
 * @throws Exception
 */
@Override public void handleRequest(HttpServerExchange exchange,RequestContext context) throws Exception {
  BsonValue responseContent=context.getResponseContent();
  if (context.getWarnings() != null && !context.getWarnings().isEmpty()) {
    if (responseContent == null) {
      responseContent=new BsonDocument();
    }
    BsonArray warnings=new BsonArray();
    if (responseContent.isDocument()) {
      if (context.getRepresentationFormat() == RequestContext.REPRESENTATION_FORMAT.PJ || context.getRepresentationFormat() == RequestContext.REPRESENTATION_FORMAT.PLAIN_JSON) {
        context.setResponseContentType(Representation.JSON_MEDIA_TYPE);
        responseContent.asDocument().append("String_Node_Str",warnings);
        context.getWarnings().forEach(w -> warnings.add(new BsonString(w)));
      }
 else {
        context.setResponseContentType(Representation.HAL_JSON_MEDIA_TYPE);
        BsonDocument _embedded;
        if (responseContent.asDocument().get("String_Node_Str") == null) {
          _embedded=new BsonDocument();
          responseContent.asDocument().append("String_Node_Str",_embedded);
        }
 else {
          _embedded=responseContent.asDocument().get("String_Node_Str").asDocument();
        }
        _embedded.append("String_Node_Str",warnings);
        context.getWarnings().forEach(w -> warnings.add(getWarningDoc(w)));
      }
    }
  }
  if (context.getRepresentationFormat() == RequestContext.REPRESENTATION_FORMAT.HAL) {
    exchange.getResponseHeaders().put(Headers.CONTENT_TYPE,Representation.HAL_JSON_MEDIA_TYPE);
  }
 else {
    exchange.getResponseHeaders().put(Headers.CONTENT_TYPE,Representation.JSON_MEDIA_TYPE);
  }
  if (!exchange.isResponseStarted()) {
    exchange.setStatusCode(context.getResponseStatusCode());
  }
  if (responseContent != null) {
    exchange.getResponseSender().send(JsonUtils.toJson(responseContent));
  }
  exchange.endExchange();
  next(exchange,context);
}