private void ensureValidRecordSize(int size) {
        if (size > maxRequestSize)
            throw new RecordTooLargeException("The message is " + size +
                    " bytes when serialized which is larger than " + maxRequestSize + ", which is the value of the " +
                    ProducerConfig.MAX_REQUEST_SIZE_CONFIG + " configuration.");
        if (size > totalMemorySize)
            throw new RecordTooLargeException("The message is " + size +
                    " bytes when serialized which is larger than the total memory buffer you have configured with the " +
                    ProducerConfig.BUFFER_MEMORY_CONFIG +
                    " configuration.");
    }
Validate that the record size isn't too large
clients/src/main/java/org/apache/kafka/clients/producer/KafkaProducer.java