Rabbitmq retrieve multiple messages using single synchronous call

You can use a QueueingConsumer implementation of Consumer interface which allows you to retrieve several messages in a single request.

 QueueingConsumer queueingConsumer = new QueueingConsumer(channel);
 channel.basicConsume(plugin.getQueueName(), false, queueingConsumer);

 for(int i = 0; i < 10; i++){
    QueueingConsumer.Delivery delivery = queueingConsumer.nextDelivery(100);//read timeout in ms
    if(delivery == null){
      break;
    }
 }

RabbitMQ's basic.get doesn't support multiple messages unfortunately as seen in the docs. The preferred method to retrieve multiple messages is to use basic.consume which will push the messages to the client avoiding multiple round trips. acks are asynchronous so your client won't be waiting for the server to respond. basic.consume also has the benefit of allowing RabbitMQ to redeliver the message if the client disconnects, something that basic.get cannot do. This can be turned off as well setting no-ack to true.

Setting basic.qos prefetch-count will set the number of messages to push to the client at any time. If there isn't a message waiting on the client side (which would return immediately) client libraries tend to block with an optional timeout.