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How to detect "Connection refused" when using MqttAsyncClient with no automatic reconnect?

I am using Eclipse Paho Java Client to connect. Here is my extended callback:
protected IMqttAsyncClient mClient;
private final MqttCallbackExtended mCallback = new MqttCallbackExtended() {
#Override
public void connectComplete(boolean reconnect, String brokerAddress) {
Log.d(LOG_TAG, "connectComplete " + brokerAddress);
}
#Override
public void connectionLost(Throwable ex) {
Log.d(LOG_TAG, "connectionLost", ex);
}
#Override
public void deliveryComplete(IMqttDeliveryToken deliveryToken) {
Log.d(LOG_TAG, "deliveryComplete " + deliveryToken);
}
#Override
public void messageArrived(String topic, MqttMessage mqttMessage) throws Exception {
Log.d(LOG_TAG, "messageArrived " + topic);
}
};
And here the connecting code:
protected void connect() throws MqttException {
Log.d(LOG_TAG, "connect");
MqttConnectOptions connectOptions = new MqttConnectOptions();
connectOptions.setCleanSession(true);
connectOptions.setAutomaticReconnect(false);
connectOptions.setUserName(MQTT_USERNAME);
connectOptions.setPassword(MQTT_PASSWORD.toCharArray());
mClient = new MqttAsyncClient(mBrokerUri, mClientName, new MemoryPersistence());
mClient.setCallback(mCallback);
mClient.connect(connectOptions);
Debug d = ((MqttAsyncClient) mClient).getDebug();
d.dumpClientDebug();
}
I do not use the automatic reconnect feature, but would like to handle reconnecting in my own custom code, since I need custom delays.
For testing purposes I do not start MQTT broker yet and try to connect.
I was hoping to detect the initial connection failure in the connectionLost callback method, but it does not get called.
The MqttException is not thrown either.
When I inspect the paho0.log.0 log file I see the failed connection there -
FINE 17-03-09 07:55:33.0726 al.TCPNetworkModule start 61 ef978a39c826cd6d4ad22f20d5abe6c236eddb060b5d765a1fe2e1d79837fcc8: Failed to create TCP socket
Throwable occurred: java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:85)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at org.eclipse.paho.client.mqttv3.internal.TCPNetworkModule.start(TCPNetworkModule.java:70)
at org.eclipse.paho.client.mqttv3.internal.ClientComms$ConnectBG.run(ClientComms.java:650)
at java.lang.Thread.run(Thread.java:745)
FINE 17-03-09 07:55:33.0727 nternal.ClientComms connectBG:run 61 ef978a39c826cd6d4ad22f20d5abe6c236eddb060b5d765a1fe2e1d79837fcc8: connect failed: unexpected exception
Throwable occurred: Unable to connect to server (32103) - java.net.ConnectException: Connection refused: connect
at org.eclipse.paho.client.mqttv3.internal.TCPNetworkModule.start(TCPNetworkModule.java:79)
at org.eclipse.paho.client.mqttv3.internal.ClientComms$ConnectBG.run(ClientComms.java:650)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:85)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at org.eclipse.paho.client.mqttv3.internal.TCPNetworkModule.start(TCPNetworkModule.java:70)
... 2 more
FINE 17-03-09 07:55:33.0732 nternal.ClientComms shutdownConnection 61 ef978a39c826cd6d4ad22f20d5abe6c236eddb060b5d765a1fe2e1d79837fcc8: state=DISCONNECTING
FINE 17-03-09 07:55:33.0732 ernal.CommsCallback stop 61 ef978a39c826cd6d4ad22f20d5abe6c236eddb060b5d765a1fe2e1d79837fcc8: stopped
FINE 17-03-09 07:55:33.0733 nal.CommsTokenStore quiesce 61 ef978a39c826cd6d4ad22f20d5abe6c236eddb060b5d765a1fe2e1d79837fcc8: resp=Client is currently disconnecting (32102)
But how to detect that connection failure in my code? (So that I could initiate the later reconnection).
UPDATE:
Reported this issue as Bug #336

Currently the only way to detect the initial connect failure of an async client is to pass it one more callback:
private final IMqttActionListener mConnectionCallback = new IMqttActionListener() {
#Override
public void onSuccess(IMqttToken asyncActionToken) {
Log.d(LOG_TAG, "onSuccess " + asyncActionToken);
// do nothing, this case is handled in mCallback.connectComplete method
}
#Override
public void onFailure(IMqttToken asyncActionToken, Throwable ex) {
Log.d(LOG_TAG, "onFailure " + asyncActionToken, ex);
// initial connect has failed
}
};
mClient = new MqttAsyncClient(mBrokerUri, mClientName, new MemoryPersistence());
mClient.setCallback(mCallback);
mClient.connect(connectOptions, null, mConnectionCallback);

How to check if MongoDB connection is established with Java?

In my app, MongoDB 3.2.4 runs on a custom port, I want to implement logic where my app will try to reach MongoDB on a custom port and if it fails it will use the default 27018 port.
In order to do that I use the following code:
String mongoClientURI = "mongodb://" + DB_SRV_USR + ":" + DB_SRV_PWD + "#" + DB_URL + ":" + DB_PORT_CUS + "/" + dbName;
MongoClientURI connectionString = new MongoClientURI(mongoClientURI);
// enable SSL connection
MongoClientOptions.builder().sslEnabled(true).build();
if (this.mongoClient == null) {
this.mongoClient = new MongoClient(connectionString);
}
// create database if doesn't exist
MongoDatabase mdb = this.mongoClient.getDatabase(dbName);
try {
this.mongoClient.getAddress();
} catch (com.mongodb.MongoSocketOpenException e) {
System.out.println("Switch to default port");
/*…use default port logic…*/
}
The problem is that this exception is not caught.
Although MongoDB throws the following exception:
com.mongodb.MongoSocketOpenException: Exception opening socket at
com.mongodb.connection.SocketStream.open(SocketStream.java:63) at
com.mongodb.connection.InternalStreamConnection.open(InternalStreamConnection.java:114)
at
com.mongodb.connection.DefaultServerMonitor$ServerMonitorRunnable.run(DefaultServerMonitor.java:128)
at java.lang.Thread.run(Thread.java:745) Caused by:
java.net.ConnectException: Connection refused: connect at
java.net.DualStackPlainSocketImpl.waitForConnect(Native Method) at
java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:85)
at
java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
at
java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at
java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172) at
java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) at
java.net.Socket.connect(Socket.java:589) at
com.mongodb.connection.SocketStreamHelper.initialize(SocketStreamHelper.java:50)
at com.mongodb.connection.SocketStream.open(SocketStream.java:58)
... 3 more
my try-catch expression can't catch this exception.
I tried multiple approaches, such as to catch:
Exception
RuntimeException
MongoSocketOpenException
MongoException
MongoCommandException
none of them doesn't work.
My questions:
How can I check if MongoDB connection is established?
How can catch the exception MongoSocketOpenException?

I use this code to check connection:
try {
mongo.getAddress();
} catch (Exception e) {
System.out.println("Database unavailable!");
mongo.close();
return;
}
Not sure here my guess would be that this.mongoClient.getAddress(); does not throw that exception, but I don't really know
EDIT: I initialized it via:
Builder builder = MongoClientOptions.builder().connectTimeout(3000);
MongoClient mongo = new MongoClient(new ServerAddress("192.168.0.1", 3000), builder.build());

java.rmi.ConnectException: Connection refused to host: 192.168.0.55

I am quite a beginner with NetBeans and Java, so I'm pretty sure my questions are very basic but trying to find the solution for 2 weeks I am totally stuck
This is the problem:
I want to implement a RMI Server Client application
So first step was trying with NetBeans to have one work from the net
I used the oracle tutorial to have the first part implemented
http://docs.oracle.com/javase/tutorial/rmi/server.html
My problem is not that the client does not connect, but that the server can't even register in the port I give him. The IP in the error message is my private IP.
This is the error message I get:
Conectando a: 127.0.0.1 / 19400 / PlanificadorTalsa
ServidorPlanificadorStarter exception:
java.rmi.ConnectException: Connection refused to host: 192.168.0.55; nested exception is:
java.net.ConnectException: Connection refused: connect
at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:619)
at sun.rmi.transport.tcp.TCPChannel.createConnection(TCPChannel.java:216)
at sun.rmi.transport.tcp.TCPChannel.newConnection(TCPChannel.java:202)
at sun.rmi.server.UnicastRef.newCall(UnicastRef.java:342)
at sun.rmi.registry.RegistryImpl_Stub.rebind(Unknown Source)
at Starter.ServidorPlanificadorStarter.main(ServidorPlanificadorStarter.java:52)
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:79)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:345)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at java.net.Socket.connect(Socket.java:538)
at java.net.Socket.<init>(Socket.java:434)
at java.net.Socket.<init>(Socket.java:211)
at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(RMIDirectSocketFactory.java:40)
at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(RMIMasterSocketFactory.java:148)
at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:613)
... 5 more
I am running windows 8.1, and disabled firewall. I am also using a security file granting all permissions
this is my java code I execute from NetBeans:
import Conexion.DatosConexion;
import Servidor.*;
import java.rmi.RemoteException;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
import java.rmi.server.UnicastRemoteObject;
public class ServidorPlanificadorStarter implements InterfazServidorPlanificador {
private static String ip;
private static String Servidor = "SERVIDORNUBE";
private static int puerto;
private static String nombreServidor;
public ServidorPlanificadorStarter(){
super();
}
public static void main(String[] args) {
if (System.getSecurityManager() == null) {
System.setSecurityManager(new SecurityManager());
}
try {
DatosConexion datos = DatosConexion.getInstance();
ip = datos.getServiceIP(Servidor);
puerto = Integer.valueOf(datos.getServicePort(Servidor));
nombreServidor = datos.getServiceName(Servidor);
System.setProperty("java.rmi.server.hostname", ip);
System.out.println("Conectando a: " + ip + " / " + puerto + " / " + nombreServidor);
InterfazServidorPlanificador engine = new ServidorPlanificadorStarter();
InterfazServidorPlanificador stub =
(InterfazServidorPlanificador) UnicastRemoteObject.exportObject(engine, puerto);
Registry registry = LocateRegistry.getRegistry();
registry.rebind(nombreServidor, stub);
System.out.println("ServidorPlanificador bound");
} catch (Exception e) {
System.err.println("ServidorPlanificadorStarter exception:");
e.printStackTrace();
}
}
}
The interface is as follows (very basic, as I have done nothing with it)
public interface InterfazServidorPlanificador extends Remote {
//void addObserver(RemoteObserver o) throws RemoteException;
}

Did you start RMI registry as in tutorial?
http://docs.oracle.com/javase/tutorial/rmi/running.html

Keep getting java.net.UnknownHostException after connecting to the internet

I'm using the Google HTTP Client Library for Java to develop a client application for a webservice of mine.
The problem is when I try to run some code like this:
private static void send() throws IOException {
HttpTransport httpTransport = new ApacheHttpTransport();
HttpRequestFactory httpRequestFactory = httpTransport
.createRequestFactory();
GenericUrl requestUrl = new GenericUrl("https://www.google.com/");
HttpRequest request = httpRequestFactory.buildGetRequest(requestUrl);
HttpResponse response = request.execute();
System.out.println(response.parseAsString());
}
public static void main(String args[]) throws InterruptedException {
boolean sent = false;
while (!sent) {
try {
send();
sent = true;
} catch (IOException e) {
e.printStackTrace();
Thread.sleep(1000);
}
}
}
I expected the program to keep trying to send the request each second until it's finnaly sent.
If I run the program with internet connected everything works fine.
If I disconnect from the internet and then run the program, I get a
java.net.UnknownHostException: www.google.com
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:178)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:579)
at sun.security.ssl.SSLSocketImpl.connect(SSLSocketImpl.java:618)
at org.apache.http.conn.ssl.SSLSocketFactory.connectSocket(SSLSocketFactory.java:333)
at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:123)
at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:147)
at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:108)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:415)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:641)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:576)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:554)
at com.google.api.client.http.apache.ApacheHttpRequest.execute(ApacheHttpRequest.java:67)
at com.google.api.client.http.HttpRequest.execute(HttpRequest.java:965)
at test.client.MyClass.send(MyClass.java:112)
at test.client.MyClass.main(MyClass.java:124)
as expected.
The problem is that I keep getting this exception even after I reconnect to the internet.
Any solutions?
Thanks
========================== UPDATE ==========================
The problem doesn't seem to be relate to the ApacheLibrary as it also happens when using the NetHttpTransport implementation.
Just replaced new ApacheHttpTransport(); by new NetHttpTransport(); on the code above generating a new looping stack trace:
java.net.UnknownHostException: www.google.com
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:178)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:579)
at sun.security.ssl.SSLSocketImpl.connect(SSLSocketImpl.java:618)
at sun.net.NetworkClient.doConnect(NetworkClient.java:175)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:432)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:527)
at sun.net.www.protocol.https.HttpsClient.<init>(HttpsClient.java:275)
at sun.net.www.protocol.https.HttpsClient.New(HttpsClient.java:371)
at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.getNewHttpClient(AbstractDelegateHttpsURLConnection.java:191)
at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:932)
at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:177)
at sun.net.www.protocol.https.HttpsURLConnectionImpl.connect(HttpsURLConnectionImpl.java:153)
at com.google.api.client.http.javanet.NetHttpRequest.execute(NetHttpRequest.java:93)
at com.google.api.client.http.HttpRequest.execute(HttpRequest.java:965)
at test.client.MyClass.send(MyClass.java:112)
at test.client.MyClass.main(MyClass.java:124)
Also I'm using a Fedora 20 Linux O.S. Kernel 3.16.6-200.
========================== UPDATE ==========================
Followed RealSkeptic's suggestion and debugged the code to find out where and how the DNS lookup is done.
I'm not familiar with java's low levew connection stuff, but I was able to produce the following almost equivalent code for the send function:
private static void send() throws IOException {
URL connUrl = new URL("https://www.google.com/");
URLConnection conn = connUrl.openConnection();
HttpURLConnection connection = (HttpURLConnection) conn;
connection.setRequestMethod("GET");
connection.setInstanceFollowRedirects(false);
connection.addRequestProperty("Accept-Encoding", "gzip");
connection.addRequestProperty("User-Agent",
"Google-HTTP-Java-Client/1.19.0 (gzip)");
connection.setReadTimeout(20000);
connection.setConnectTimeout(20000);
boolean successfulConnection = false;
try {
connection.connect();
//NetHttpResponse response = new NetHttpResponse(connection);
successfulConnection = true;
} finally {
if (!successfulConnection) {
connection.disconnect();
}
}
}
It's lacking on the response treatment.
With the code above, I keep getting the same result: A looping stacktrace that never ends.
Does anyone knows how to solve that?
Some enviroment information:
$cat /etc/resolv.conf
# Generated by NetworkManager
domain velox.com.br
search velox.com.br
nameserver 208.67.222.222
nameserver 8.8.8.8
$ java -version
java version "1.7.0_71"
OpenJDK Runtime Environment (fedora-2.5.3.0.fc20-x86_64 u71-b14)
OpenJDK 64-Bit Server VM (build 24.65-b04, mixed mode)

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.