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RabbitMQ Java Consumer app best practice for Ubuntu linux deployment

I'm studing how RabbitMQ works with Java, it is almost clear how Producer works and how to implement the Consumer, but I'm still not sure how to deploy the Consumer application to server with a correct threading handling.
Let's say I have a web-application that has to sent some transaction email as producer, this application will push in the queue the messages and it is managed by a container, like Tomcat, that increase/descrease threads to serve multiple requests.
What is the best practice to deployt the consumer application?
I have read many tutorials and the RabbitMQ commands are well explained, usually this is the code (from official RabbitMq Hello World):
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.DeliverCallback;
import java.nio.charset.StandardCharsets;
public class Recv {
private final static String QUEUE_NAME = "hello";
public static void main(String[] argv) throws Exception {
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("localhost");
Connection connection = factory.newConnection();
Channel channel = connection.createChannel();
channel.queueDeclare(QUEUE_NAME, false, false, false, null);
System.out.println(" [*] Waiting for messages. To exit press CTRL+C");
DeliverCallback deliverCallback = (consumerTag, delivery) -> {
String message = new String(delivery.getBody(), StandardCharsets.UTF_8);
System.out.println(" [x] Received '" + message + "'");
};
channel.basicConsume(QUEUE_NAME, true, deliverCallback, consumerTag -> { });
}
}
However it is not clear to me how I should run this application in my server (sure I can start it by command line!) and how am I sure the process will not crash for some reason?
Should I put the channel opening commands in a loop inside a try/catch to be sure it will not exit?
Am I'm in charge of handling thread pool opening/increasing?
Does exists something for this purpose?

Reactor rabbitmq AlreadyClosedException

In my project I am using Springboot version 2.1.2.RELEASE, reactor-rabbitmq version 1.0.0.RELEASE. I am creating rabbit receiver, subscribe it and process messagess with manual ack. But after some time it can be after an hour or after 1-2 days of work, I am getting heartbeat missing error, than channel is closing and I get "com.rabbitmq.client.AlreadyClosedException: connection is already closed due to connection error; cause: java.io.IOException: Connection reset by peer" and my receiver no longer receive messages. It works only after restart.
Rabbit client has
connectionFactory.setAutomaticRecoveryEnabled(true);
and
connectionFactory.setTopologyRecoveryEnabled(true);
so it should auto-recovery by default, but it doesn't work.
public void startReceiver(int parallelism) {
ConnectionFactory connectionFactory = new ConnectionFactory();
connectionFactory.useNio();
connectionFactory.setPort(5672);
connectionFactory.setUsername("guest");
connectionFactory.setPassword("guest");
connectionFactory.setVirtualHost("/");
connectionFactory.setRequestedHeartbeat(10);
Address[] addresses = {new Address("localhost")};
ReceiverOptions receiverOptions = new ReceiverOptions()
.connectionFactory(connectionFactory)
.connectionSupplier(cf -> cf.newConnection(addresses, "receiver"))
.connectionSubscriptionScheduler(Schedulers.elastic());
Receiver receiver = RabbitFlux.createReceiver(receiverOptions);
receiver.consumeManualAck("test-data", new ConsumeOptions().qos(200))
.doOnSubscribe(s -> System.out.println("Receiver started."))
.retry()
.parallel(parallelism)
.runOn(Schedulers.newParallel("parallel-receiver", parallelism))
.doOnNext(d -> processMessage(d))
.subscribe();
}
private void processMessage(AcknowledgableDelivery message) {
try {
//some processing
} catch (Exception e) {
e.printStackTrace();
}
message.ack();
}
I getting errors
com.rabbitmq.client.MissedHeartbeatException: Heartbeat missing with heartbeat = 10 seconds,
at com.rabbitmq.client.impl.AMQConnection.handleHeartbeatFailure(AMQConnection.java:686) ~[amqp-client-5.5.1.jar!/:5.5.1],
at com.rabbitmq.client.impl.nio.NioLoop.lambda$handleHeartbeatFailure$0(NioLoop.java:273) [amqp-client-5.5.1.jar!/:5.5.1],
at java.lang.Thread.run(Thread.java:748) ~[na:1.8.0_181],
reactor.rabbitmq.Receiver : Cancelling consumer amq.ctag--x02OWhVo3_DPutsPQ0qDw consuming from test-data,
reactor.core.Exceptions$ErrorCallbackNotImplemented: com.rabbitmq.client.AlreadyClosedException: connection is already closed due to connection error; cause: java.io.IOException: Connection reset by peer,
Caused by: com.rabbitmq.client.AlreadyClosedException: connection is already closed due to connection error; cause: java.io.IOException: Connection reset by peer,
at com.rabbitmq.client.impl.AMQChannel.ensureIsOpen(AMQChannel.java:257) ~[amqp-client-5.5.1.jar!/:5.5.1],
at com.rabbitmq.client.impl.AMQChannel.transmit(AMQChannel.java:426) ~[amqp-client-5.5.1.jar!/:5.5.1],
at com.rabbitmq.client.impl.AMQChannel.transmit(AMQChannel.java:420) ~[amqp-client-5.5.1.jar!/:5.5.1],
at com.rabbitmq.client.impl.recovery.RecoveryAwareChannelN.basicAck(RecoveryAwareChannelN.java:93) ~[amqp-client-5.5.1.jar!/:5.5.1],
at com.rabbitmq.client.impl.recovery.AutorecoveringChannel.basicAck(AutorecoveringChannel.java:428) ~[amqp-client-5.5.1.jar!/:5.5.1],
at reactor.rabbitmq.AcknowledgableDelivery.ack(AcknowledgableDelivery.java:56) ~[reactor-rabbitmq-1.0.0.RELEASE.jar!/:1.0.0.RELEASE],
at reactor.rabbitmq.AcknowledgableDelivery.ack(AcknowledgableDelivery.java:73) ~[reactor-rabbitmq-1.0.0.RELEASE.jar!/:1.0.0.RELEASE],

Amqp client not connecting to activemq server.

I'm trying connect from a amqp client to a aqtivemq server with default settings. It always gives the error message saying connection refused. Then I tried it with a rabbitmq server instead of a activemq server and it works fine. I wonder whether activemq needs a linux library to communicate.
Activemq server versions used which does not connects: 5.4.2 / 5.10.0
Rabitmq version used: 3.3.5
rabitmq sample client code
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.Channel;
public class Cache {
private final static String QUEUE_NAME = "hello";
public static void main(String[] argv)
throws java.io.IOException {
//creating the connection factory
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("localhost");
//Creating a connection to the server
Connection connection = factory.newConnection();
Channel channel = connection.createChannel();
//declaring a queuw
channel.queueDeclare(QUEUE_NAME, false, false, false, null);
String message = "Hello World!";
//publishing the queue the queue
channel.basicPublish("", QUEUE_NAME, null, message.getBytes());
System.out.println(" [x] Sent '" + message + "'");
//closing the connection
channel.close();
connection.close();
}
}
Fails in the following line of code
//Creating a connection to the server
Connection connection = factory.newConnection();
How can I solve this issue ?

I found a similar issue and I fixed checking the exchange declared was equals to the channel used to publish, in this way:
#Test
public void test() throws KeyManagementException, NoSuchAlgorithmException, URISyntaxException, IOException {
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("10.211.55.20");
factory.setPort(5672);
factory.setVirtualHost("/");
factory.setUsername("guest");
factory.setPassword("guest");
Connection connection = factory.newConnection();
Channel channel = connection.createChannel();
channel.exchangeDeclare("KipcastDirect", "direct",
true, /* durable */
true, /* autodelete */
null); /* */
byte[] messageBodyBytes = "Hello, world!".getBytes();
AMQP.BasicProperties.Builder basic = new AMQP.BasicProperties.Builder();
AMQP.BasicProperties minBasic = basic.build();
minBasic = basic.priority(0).deliveryMode(1).build();
channel.basicPublish("KipcastDirect", "KipcastRouting", minBasic, messageBodyBytes);
System.out.println(" [x] Sent ");
channel.close();
}
Please be carefoul: the URI (from and to) on Camel Spring DSL context and JUnit class must refer to same Exchange and Queue to prevent a reply-text=PRECONDITION_FAILED – parameters for queue ‘QUEUE’ in vhost ‘/’ not equivalen error or similar. To check the queues / exchanges configuration parameter use:
rabbitmqadmin -V / list queue
rabbitmqadmin -V test list exchanges
Take a look to this: http://www.andreagirardi.it/blog/camel-and-rabbitmq-finally-how-to/

RabbitMQ "Hello World" example gives "Connection Refused"

II'm trying to make the "hello world" application from here: RabbitMQ Hello World
Here is the code of my producer class:
package com.mdnaRabbit.producer;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.Channel;
import java.io.IOException;
public class App {
private final static String QUEUE_NAME = "hello";
public static void main( String[] argv) throws IOException{
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("localhost");
Connection connection = factory.newConnection();
Channel channel = connection.createChannel();
channel.queueDeclare(QUEUE_NAME, false, false, false, null);
String message = "Hello World!";
channel.basicPublish("", QUEUE_NAME, null, message.getBytes());
System.out.println(" [x] Sent" + "'");
channel.close();
connection.close();
}
}
And here what I get when implement this:
Exception in thread "main" java.net.ConnectException: Connection refused
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:391)
at java.net.Socket.connect(Socket.java:579)
at com.rabbitmq.client.ConnectionFactory.createFrameHandler(ConnectionFactory.java:445)
at com.rabbitmq.client.ConnectionFactory.newConnection(ConnectionFactory.java:504)
at com.rabbitmq.client.ConnectionFactory.newConnection(ConnectionFactory.java:533)
at com.mdnaRabbit.producer.App.main(App.java:16)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)
Process finished with exit code 1
What is causing this?
I found the solution to my problem here Error in making a socket connection

To deal with it I installed RabbitMQ server. If rabbitmq-server is not installed this error will be thrown.
Make sure you have installed RabbitMQ server and it's up and running by hitting http://localhost:15672/

I got this "Connection Refused" error as well:
Exception in thread "main" java.net.ConnectException: Connection refused
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:579)
at com.rabbitmq.client.impl.FrameHandlerFactory.create(FrameHandlerFactory.java:32)
at com.rabbitmq.client.ConnectionFactory.newConnection(ConnectionFactory.java:588)
at com.rabbitmq.client.ConnectionFactory.newConnection(ConnectionFactory.java:612)
at ReceiveLogs.main(ReceiveLogs.java:14)
I had made a mistake by setting the IP address from inside /etc/rabbitmq/rabbitmq-env.conf to the wrong ip address:
NODE_IP_ADDRESS=10.0.1.45
I removed this configuration parameter and the error goes away.

I solved this problem simply by executing:
sudo rabbitmq-server

Start the Rabbit MQ Server. The batch file to start this server is present under rabbitmq_server-3.6.0\sbin>rabbitmq-server.bat start then it will work.

In my case it gave me the following error trying to start the server
<Rabbit intall path>\rabbitmq_server-3.6.0\sbin>rabbitmq-server.bat start
ERROR: epmd error for host Protocol: inet_tcp: register/listen error: econnrefused: nxdomain (non-existing domain)
What I did was add in my host file the following line:
127.0.0.1 localhost
And then the rabbitmq-server started. After this I didn't get the connection refuse error anymore. Hope this helps.

Sometimes you just gotta reboot a mac. Tried all the other solutions here and other things from different questions, and as dumb as it sounds, a reboot is what finally got it back to running and able to reach http://localhost:15672/
This was after I had done a brew upgrade (which is what probably put me in a bad state).

You have to start Rabbit MQ Serever
In windows file name: RabbitMQ Service - start
You can use this code:
import java.io.IOException;
import java.util.ResourceBundle;
import java.util.concurrent.TimeoutException;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
public class NewTaskController implements Runnable {
private final String message;
private static final String EXCHANGE_NAME = "test";
private static final String ROUTING_KEY = "test";
public NewTaskController(final String message) {
this.message = message;
}
#Override
public void run() {
//getting data from application.properties
//for the rabbit_mq configuration
ResourceBundle mRB = ResourceBundle.getBundle("application");
System.out.println("*****NewTaskController************"+mRB.getString("rabbitmq.port"));
String rabbitmq_username = mRB.getString("rabbitmq.username");
String rabbitmq_password = mRB.getString("rabbitmq.password");
String rabbitmq_hostname = mRB.getString("rabbitmq.hostname");
int rabbitmq_port = Integer.parseInt(mRB.getString("rabbitmq.port"));
ConnectionFactory factory = new ConnectionFactory();
factory.setUsername(rabbitmq_username);
factory.setPassword(rabbitmq_password);
factory.setHost(rabbitmq_hostname);
factory.setPort(rabbitmq_port);
Connection conn;
try {
conn = factory.newConnection();
Channel channel = conn.createChannel();
channel.exchangeDeclare(EXCHANGE_NAME, "direct", true);
String queueName = channel.queueDeclare().getQueue();
System.out.println(queueName);
channel.queueBind(queueName, EXCHANGE_NAME, ROUTING_KEY);
System.out.println("Producing message: " + message + " in thread: " + Thread.currentThread().getName());
channel.basicPublish(EXCHANGE_NAME, ROUTING_KEY, null, message.getBytes());
try {
channel.close();
} catch (TimeoutException e) {
e.printStackTrace();
}
conn.close();
} catch (IOException | TimeoutException e) {
e.printStackTrace();
}
}
}
application.properties file:
rabbitmq.username=guest
rabbitmq.password=guest
rabbitmq.hostname=localhost
rabbitmq.port=5672

The simple fix is indeed, rabbitmq-server, if you already have RabbitMQ installed locally.
I encountered this issue as a firewall issue after migrating from Mac OS X Sierra to High Sierra. I already had RabbitMQ installed. However, I kept getting this Connection Refused error. I had to do the following:
brew uninstall rabbitmq
brew install rabbitmq
rabbitmq-server
(and allow firewall permissions)
Run app locally.

accessing salesforce from java using web service connector

I am trying to connect to Salesforce from a java class (on my local machine). I have used the WSC-22.jar (webservice connector) and used the same as the library in eclipse. I have also parsed the enterprise wsdl to a jar and uploaded the library in the eclipse. I am running the below java class which is error out.
package wsc;
import com.sforce.soap.enterprise.Connector;
import com.sforce.soap.enterprise.DeleteResult;
import com.sforce.soap.enterprise.EnterpriseConnection;
import com.sforce.soap.enterprise.Error;
import com.sforce.soap.enterprise.QueryResult;
import com.sforce.soap.enterprise.SaveResult;
import com.sforce.soap.enterprise.sobject.Account;
import com.sforce.soap.enterprise.sobject.Contact;
import com.sforce.ws.ConnectionException;
import com.sforce.ws.ConnectorConfig;
public class main {
static final String USERNAME = "username";
static final String PASSWORD = "password + sec token";
static EnterpriseConnection connection;
public static void main(String[] args) {
ConnectorConfig config = new ConnectorConfig();
config.setUsername(USERNAME);
config.setPassword(PASSWORD);
//config.setTraceMessage(true);
try {
connection = com.sforce.soap.enterprise.Connector.newConnection(config);
// display some current settings
System.out.println("Auth EndPoint: "+config.getAuthEndpoint());
System.out.println("Service EndPoint: "+config.getServiceEndpoint());
System.out.println("Username: "+config.getUsername());
System.out.println("SessionId: "+config.getSessionId());
// run the different examples
queryContacts();
createAccounts();
updateAccounts();
deleteAccounts();
} catch (ConnectionException e1) {
System.out.println("hello world");
e1.printStackTrace();
}
}
//somemore code----
ERROR MESSAGE:
com.sforce.ws.ConnectionException: Failed to send request to
https://login.salesforce.com/services/Soap/c/26.0
at com.sforce.ws.transport.SoapConnection.send(SoapConnection.java:120)
at com.sforce.soap.enterprise.EnterpriseConnection.login(EnterpriseConnection.java:1)
at com.sforce.soap.enterprise.EnterpriseConnection.<init>(EnterpriseConnection.java:1)
at com.sforce.soap.enterprise.Connector.newConnection(Connector.java:1)
at wsc.main.main(main.java:32)
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:351)hello world
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:213)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:200)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
at java.net.Socket.connect(Socket.java:529)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.connect(SSLSocketImpl.java:570)
at com.sun.net.ssl.internal.ssl.BaseSSLSocketImpl.connect(BaseSSLSocketImpl.java:141)
at sun.net.NetworkClient.doConnect(NetworkClient.java:163)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:411)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:525)
at sun.net.www.protocol.https.HttpsClient.<init>(HttpsClient.java:272)
at sun.net.www.protocol.https.HttpsClient.New(HttpsClient.java:329)
at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.getNewHttpClient(AbstractDelegateHttpsURLConnection.java:172)
at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:966)
at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:158)
at sun.net.www.protocol.http.HttpURLConnection.getOutputStream(HttpURLConnection.java:1031)
at sun.net.www.protocol.https.HttpsURLConnectionImpl.getOutputStream(HttpsURLConnectionImpl.java:230)
at com.sforce.ws.transport.JdkHttpTransport.connectRaw(JdkHttpTransport.java:133)
at com.sforce.ws.transport.JdkHttpTransport.connectLocal(JdkHttpTransport.java:97)
at com.sforce.ws.transport.JdkHttpTransport.connectLocal(JdkHttpTransport.java:92)
at com.sforce.ws.transport.JdkHttpTransport.connect(JdkHttpTransport.java:88)
at com.sforce.ws.transport.SoapConnection.send(SoapConnection.java:94)
I am unable to figure out how to solve this issue. As the error message says "Falied to connect to http://login.salesforce.com./...", should I enable some setting in Eclipse??
Regards
Sam

Are you behind a proxy ?
If so, enable proxy settings in eclipse preferences general → network

...
String proxyHost = getUserInput("Enter proxy host:");
String proxyPort = getUserInput("Enter proxy port:");
try {
...
if(proxyHost!=null && !proxyHost.trim().equals("")){
config.setProxy(proxyHost, Integer.valueOf(proxyPort));
}
...