How to Fix java.net.ConnectException: Connection refused: connect in Java
java.net.ConnectException: Connection refused Error – Possible reasons
Connection refused is a clear case of a client trying to connect on a TCP port but not being able to succeed. Here are some of the possible reasons why java.net.ConnectException: Connection refused: connect comes:
How to solve java.net.ConnectException: Connection refused
19 comments :
at com.mysql.jdbc.NonRegisteringDriver.connect . why we get this exception and how can we resolve it..can anyone tell me please
java.net.ConnectException: Connection refused: connect , is pretty general error. Real error is always behind, I suggest looking top level error and caused by clause. This will give you more ideas. In simple words, this error just says that your client and server is not able to connect, but doesn't tell anything about why connection is not happening. There could be thousands of reason of a client and server not connecting including environment issues, host settings, network settings and application settings itself.
Hello there, I am getting following Connection refused: connect exception while trying to send an email from localhost. I am using smpt port 25
com.sun.mail.util.MailConnectException: Couldn't connect to host, port: localhost, 25; timeout -1;
nested exception is:
java.net.ConnectException: Connection refused: connect
at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1984)
at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:656)
at javax.mail.Service.connect(Service.java:345)
at javax.mail.Service.connect(Service.java:226)
at javax.mail.Service.connect(Service.java:175)
at javax.mail.Transport.send0(Transport.java:253)
at javax.mail.Transport.send(Transport.java:124)
at Testing.main(Testing.java:62)
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:339)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:579)
at java.net.Socket.connect(Socket.java:528)
at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:301)
at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:229)
at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1950)
. 7 more
Please suggest what is wrong?
I am also facing this type of problem. please suggest me
Exception in thread "main" org.springframework.mail.MailSendException: Mail server connection failed; nested exception is javax.mail.MessagingException: Could not connect to SMTP host: smtp.gmail.com, port: 465;
nested exception is:
java.net.ConnectException: Connection refused. Failed messages: javax.mail.MessagingException: Could not connect to SMTP host: smtp.gmail.com, port: 465;
nested exception is:
java.net.ConnectException: Connection refused; message exception details (1) are:
Failed message 1:
javax.mail.MessagingException: Could not connect to SMTP host: smtp.gmail.com, port: 465;
nested exception is:
java.net.ConnectException: Connection refused
at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1227)
at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:322)
at javax.mail.Service.connect(Service.java:236)
at org.springframework.mail.javamail.JavaMailSenderImpl.doSend(JavaMailSenderImpl.java:389)
at org.springframework.mail.javamail.JavaMailSenderImpl.send(JavaMailSenderImpl.java:306)
at org.springframework.mail.javamail.JavaMailSenderImpl.send(JavaMailSenderImpl.java:296)
at com.aa.meals.mail.MealsMailSenderBean.sendMail(MealsMailSenderBean.java:21)
at com.aa.common.log.TestMail.main(TestMail.java:14)
help my java is not allowing me to install it says the installer cannot proceed with the current internet settings
following is my java code error.
Exception in thread "main" java.net.UnknownHostException: ubaid.tk
could you help me.
cp –p mail.cf mail.cf.orig
#inet_interfaces = $myhostname, localhost
#inet_interfaces = $myhostname, localhost
Test connection from unix prompt
telnet pslab17 25
Connected to pslab17.
Escape character is '^]'.
220 pslab17.localdomain ESMTP Postfix
Connection closed by foreign host.
google "setting java options -D ipv4=true"
Please check for the port number as its already in use by another application , if yes, kill that process and restart the server.like
go to command prompt—>type netstat -ano | find "port number"
you will find list of applications using your port number.. then just type
taskkill /pid "pid of port no" /f
restart server then it should work..
Hello
I am getting java.net.SocketException: Network is down: listen failed exception
what may be the reason?
Hostname maps to multiple IP addresses and one of the IP address is down. Some network libraries automatically try a connection to second server while others need to have code in the application. nslookup hostname. $telnet hostname 25 needs to be replaced with $telnet ip-address 25
An important point to note is that if you are using alias e.g. DNS to connect to database or servers then you must remember that JVM can cache DNS value to avoid looking up again and again when a connection needs to be made. This is all ok and improves performance but also risky in the even to fail-over when DNS points to another server. There is a JVM option to configure this behavior e.g. how long to cache, cache or not etc, worth looking.
java.net.ConnectException: Connection timed out: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:351)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:213)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:200)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
at java.net.Socket.connect(Socket.java:529)
at java.net.Socket.connect(Socket.java:478)
at sun.net.NetworkClient.doConnect(NetworkClient.java:163)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:388)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:523)
at sun.net.www.http.HttpClient.(HttpClient.java:227)
at sun.net.www.http.HttpClient.New(HttpClient.java:300)
at sun.net.www.http.HttpClient.New(HttpClient.java:317)
at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:970)
at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:911)
at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:836)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1172)
at java.net.URL.openStream(URL.java:1010)
at com.lowagie.text.Image.getInstance(Unknown Source)
at com.lowagie.text.Image.getInstance(Unknown Source)
at jsp_servlet._health_ecard.__hlth_idcard._jspService(__hlth_idcard.java:217)
at weblogic.servlet.jsp.JspBase.service(JspBase.java:34)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227)
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:301)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:184)
at weblogic.servlet.internal.RequestDispatcherImpl.invokeServlet(RequestDispatcherImpl.java:526)
at weblogic.servlet.internal.RequestDispatcherImpl.forward(RequestDispatcherImpl.java:253)
at org.apache.struts.action.RequestProcessor.doForward(RequestProcessor.java:1078)
at org.apache.struts.action.RequestProcessor.processForwardConfig(RequestProcessor.java:396)
at com.allianz.weo.struts.WeoRequestProcessor.processForwardConfig(WeoRequestProcessor.java:141)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:232)
at com.allianz.weo.struts.WeoRequestProcessor.process(WeoRequestProcessor.java:37)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:449)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227)
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:301)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:184)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.wrapRun(WebAppServletContext.java:3729)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3696)
at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)
at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:120)
at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2273)
at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2179)
at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1490)
at weblogic.work.ExecuteThread.execute(ExecuteThread.java:256)
at weblogic.work.ExecuteThread.run(ExecuteThread.java:221)
org.openqa.selenium.WebDriverException: java.net.ConnectException: Failed to connect to localhost
@Unknown, check if your server or Java application is running or port is correct.
My javanet connection on scratch day
hello Lokesh, what does that mean? are you getting any error?
INLT3635@Thread[main,5,main]@1655277498232
com.freedomgroup.common.communicator.TFGHttpClient:
Connection refused: connect:
Connection refused: connect
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at com.freedomgroup.common.exception.TFGExceptionUtility.createThrowable(TFGExceptionUtility.java:328)
at com.freedomgroup.common.exception.TFGExceptionUtility.createSessionException(TFGExceptionUtility.java:239)
at com.freedomgroup.common.gui.request.TFGInvocationHandler.invokeService(TFGInvocationHandler.java:97)
at com.freedomgroup.common.gui.request.TFGInvocationHandler.invokeService(TFGInvocationHandler.java:239)
at com.freedomgroup.common.gui.request.TFGInvocationHandler.invoke(TFGInvocationHandler.java:157)
at com.sun.proxy.$Proxy0.getSystemDeploymentName(Unknown Source)
at com.freedomgroup.policystar.gui.util.TFGPolicyStarUtilities.getSystemDeploymentName(TFGPolicyStarUtilities.java:2460)
at com.freedomgroup.policystar.gui.base.TFGPolicyStarGUIRunner.main(TFGPolicyStarGUIRunner.java:425)
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: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:606)
at java.net.Socket.connect(Socket.java:555)
at java.net.Socket.(Socket.java:451)
at java.net.Socket.(Socket.java:303)
at org.apache.commons.httpclient.protocol.DefaultProtocolSocketFactory.createSocket(DefaultProtocolSocketFactory.java:80)
at org.apache.commons.httpclient.protocol.DefaultProtocolSocketFactory.createSocket(DefaultProtocolSocketFactory.java:122)
at org.apache.commons.httpclient.HttpConnection.open(HttpConnection.java:707)
at org.apache.commons.httpclient.MultiThreadedHttpConnectionManager$HttpConnectionAdapter.open(MultiThreadedHttpConnectionManager.java:1361)
at org.apache.commons.httpclient.HttpMethodDirector.executeWithRetry(HttpMethodDirector.java:387)
at org.apache.commons.httpclient.HttpMethodDirector.executeMethod(HttpMethodDirector.java:171)
at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:397)
at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:323)
at com.freedomgroup.common.communicator.TFGHttpClient.processRequest(TFGHttpClient.java:227)
at com.freedomgroup.common.communicator.TFGHttpRequestHandler.processRequest(TFGHttpRequestHandler.java:99)
at com.freedomgroup.common.gui.request.TFGInvocationHandler.invokeService(TFGInvocationHandler.java:79)
. 5 more
How can I help? did you checked if the server is up and running and whether you can connect to the server? If you are running your from home then make sure you check that VPN is connected to your office network as well.
[Solved] java.net.ConnectException: Connection refused
Java is famous for networking applications. Java programmers have written socket programming for client server-based architecture. Most of the socket programming uses TCP-IP protocol for communication between client-server. Remote Method Invocation (RMI) also uses the TCP-IP protocol for communication. Sometime, it will generate java.net.ConnectException Connection refused exception for some communication channel error.
In this article, we will describe why this communication channel exception occurs in the first part, and in the second part, we will explain how to solve it.
1. Reasons for java.net.ConnectException
1. PORT or IP is incorrect: If PORT or IP is wrong, then the client will not be able to connect to the desired server. Then it will get this kind of exception.
2. Server is stopped: Suppose a server administration gave some IP address and PORT to you to access the server. But he stopped the server, but your client programs trying to access the server with administrator provided credentials, the client program will get the exception.
3. Protocol mismatch: We know that HTTP, RMI, Websocket, etc. uses TCP as the underlying protocol. HTTP request will start with http:// and RMI protocol starts with rmi// or WebSocket protocol start with ws://. If we request an HTTP request with rmi protocol, it will throw the java.net.ConnectException.
4. Server running in the different port: If server administrator provides you an IP and PORT but server running in a different port, it will give java.net.ConnectException Connection refused.
5. Server or client is not in the network: If the client or server is disconnected from the network, then the client will not be able to find out the server. When the client program will not be able to find out the server, we will get this exception.
6. Firewall Restriction: In the networking world, many malware or virus programs can affect the network or personal computer that is connected to the public network. The different organizations put a firewall to the network to prevent this unwanted attack of various harmful products. Some companies allow internal networks only. If your server programs run on this network and the client IP is not allowed in this network, it will get the exception java.net.ConnectException Connection refused.
2. How to Solve this Exception:
The client can connect with the server easily when
a. The server is running in the IP and PORT provided by the server administrator.
b. There is no restriction on the network.
c. The client and server are on the network.
We have to check the above things first before connecting to the server. We can test this in different ways.
1. We can check the IP and PORT are available for the client by using telnet.
For example, you can use this command to check IP and PORT are running or not.
2. We can check the IP is available for the client by pinging IP provided by the server administrator.
For example, you can ping with this command
You will get below result:
3. Practical Example:
1. When we try to connect a database server like MYSQL or Oracle, but IP or PORT is not running or not accessible, then we get the exception java.net.ConnectException.
2. When a mail server is not running the desired PORT or IP, we will get this kind of exception.
3. When an application running in a different PORT or IP, but the client tries to connect, we will get this exception.
Example with Java Code
If we execute the following command from the command line, we will get the desired exception
How to solve java.net.ConnectException: Connection refused
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The simplest remedy is to figure out what is causing java.net.ConnectException: Connection refused. What is most significant in this case is the approach taken in determining the correct cause and solution. Here are some suggestions that may assist you in determining the root cause.
- First, ping the destination host; if the host is ping-able, this indicates that both the client and server machines are connected to the network.
- Use telnet to establish a connection to the server’s host and port. Inability to connect indicates that there is a problem with your client software code. Additionally, by examining the telnet output, you will be able to determine whether the server is functioning or not, as well as whether the server is severing the connection from the client.
Reasons For The Error: java.net.ConnectException: Connection refused
Connection rejected is a clear example of a client attempting to establish a connection on a TCP port but failing. Here are some of the possible causes of the error that could be encountered:
Reason 1: Client and Server, either or both of them are not in the network.
The fact that client and server are not linked to a LAN, the internet, or any other network is a possibility, and in that case, Java will throw an error message.This error message is the same one we are dealing with: java.net.ConnectException: Connection refused.
Reason 2: Server is not running
The second most frequently encountered issue is that the server is not up and operating. In that scenario, you will additionally receive java.net. ConnectException: Connection refused error.
What we don’t like about it is that no matter what the reason for the issue is, it always produces the same error message.
Furthermore, you can use the following networking commands, such as ping to determine whether the server is up and running and listening on the specified port.
Reason 3: The server is running but not listening on the port, a client is trying to connect.
This is yet another typical reason for “java.net.ConnectException: Connection refused “, in which the server is up and running but is listening on a different port than usual. It’s difficult to figure out this case unless you sit down and think about it, then you can verify the settings. If you are working on a large project with a hierarchical configuration file, it is possible that either the default configuration or or another setting is taking precedence over your current configuration.
Reason 4: Firewall is not permitted for host-port combination
Firewalls are used to secure almost every corporate network today. It is necessary to raise firewall requests from both sides when connecting to another company’s network, for example, when starting a FIX session to the broker in an Electronic Trading System, in order to verify that the IP address and port number of the other company’s network are permitted. If the firewall is not allowing the connection, you will also receive the same java.net.ConnectException: Connection refused exception in Java application.
Reason 5: Host Port combination is incorrect.
This could be yet another explanation for the existence of java.net.Connection refused. You should consider the possibility that either you are supplying an invalid host port combination or that a previously used host port combination has been modified on the server’s end. Check for the most recent configuration on both the client and server sides to avoid connection denied exceptions from occurring.
Reason 6: Incorrect protocol in Connection String
TCP is the underlying protocol for several high-level protocols, including HTTP, RMI, and others. TCP is a transmission control protocol. Ensure that you are giving the correct connection string to the server, which begins with the protocol that the server expects, for example, if the server has exposed its service via RMI, the connection string should begin with rmi:/
How to fix java.lang.OutOfMemoryError: Java heap space?
An easy technique to resolve OutOfMemoryError in Java is to increase the maximum heap size using JVM options “-Xmx512M”, which will resolve your OutOfMemoryError quickly.
Alternative Method:
The second method to resolve OutOfMemoryError in Java is more difficult and occurs when you don’t have much memory and even after increasing the maximum heap size you still get java.lang.OutOfMemoryError; in this situation, you should definitely profile your programme and look for any memory leak.
You may also check your heap dump with Eclipse Memory Analyzer or any profiler such as Netbeans or JProbe. This is a difficult solution that will take some time to investigate and detect memory leaks.
How to solve java.lang.OutOfMemoryError: PermGen space?
As stated in the above paragraph, the OutOfMemory issue in Java occurs when the heap’s Permanent generation is depleted. To resolve this OutOfMemoryError in Java, use the JVM option “-XX: MaxPermSize” to raise the heap size of the Perm area.
You can also provide the initial size of Perm Space with “-XX: PermSize,” and by retaining both the initial and maximum Perm Space, you can avoid certain entire garbage collection that may occur when Perm Space is resized.
How to Fix java.net.ConnectException: Connection refused: connect in Java?
java.net.ConnectException: Connection refused: connect is the most frequent kind of occurring networking exception in Java whenever the software is in client-server architecture and trying to make a TCP connection from the client to the server. We need to handle the exception carefully in order to fulfill the communication problem. First, let us see the possible reasons for the occurrence of java.net.ConnectException: Connection refused.
- As client and server involved, both should be in a network like LAN or internet. If it is not present, it will throw an exception on the client-side.
- If the server is not running. Usually ports like 8080, (for tomcat), 3000 or 4200 (for react/angular), 3306(MySQL), 27017(MongoDB) or occupied by some other agents or totally down i.e. instance not started.
- Sometimes a server may be running but not listening on port because of some overridden settings etc.
- Usually, for security reasons, the Firewall will be there, and if it is disallowing the communication.
- By mistake, the wrong port is mentioned in the port or the random port generation number given.
- Connection string information wrong. For example:
Implementation: Here we are using MySQL database connectivity and connection info should be of this format. Now let us see the ways to fixing the ways of java.net.ConnectException: Connection refused. Ping the destination host by using the commands as shown below:
There are tools like “Putty” are available to communicate, and it is a free implementation of Telnet and SSH for Windows and Unix.
How to Fix java.net.ConnectException: Connection refused: connect in Java
java.net.ConnectException: Connection refused Error – Possible reasons
Connection refused is a clear case of a client trying to connect on a TCP port but not being able to succeed. Here are some of the possible reasons why java.net.ConnectException: Connection refused: connect comes:
How to solve java.net.ConnectException: Connection refused
19 comments :
at com.mysql.jdbc.NonRegisteringDriver.connect . why we get this exception and how can we resolve it..can anyone tell me please
java.net.ConnectException: Connection refused: connect , is pretty general error. Real error is always behind, I suggest looking top level error and caused by clause. This will give you more ideas. In simple words, this error just says that your client and server is not able to connect, but doesn't tell anything about why connection is not happening. There could be thousands of reason of a client and server not connecting including environment issues, host settings, network settings and application settings itself.
Hello there, I am getting following Connection refused: connect exception while trying to send an email from localhost. I am using smpt port 25
com.sun.mail.util.MailConnectException: Couldn't connect to host, port: localhost, 25; timeout -1;
nested exception is:
java.net.ConnectException: Connection refused: connect
at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1984)
at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:656)
at javax.mail.Service.connect(Service.java:345)
at javax.mail.Service.connect(Service.java:226)
at javax.mail.Service.connect(Service.java:175)
at javax.mail.Transport.send0(Transport.java:253)
at javax.mail.Transport.send(Transport.java:124)
at Testing.main(Testing.java:62)
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:339)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:579)
at java.net.Socket.connect(Socket.java:528)
at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:301)
at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:229)
at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1950)
. 7 more
Please suggest what is wrong?
I am also facing this type of problem. please suggest me
Exception in thread "main" org.springframework.mail.MailSendException: Mail server connection failed; nested exception is javax.mail.MessagingException: Could not connect to SMTP host: smtp.gmail.com, port: 465;
nested exception is:
java.net.ConnectException: Connection refused. Failed messages: javax.mail.MessagingException: Could not connect to SMTP host: smtp.gmail.com, port: 465;
nested exception is:
java.net.ConnectException: Connection refused; message exception details (1) are:
Failed message 1:
javax.mail.MessagingException: Could not connect to SMTP host: smtp.gmail.com, port: 465;
nested exception is:
java.net.ConnectException: Connection refused
at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1227)
at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:322)
at javax.mail.Service.connect(Service.java:236)
at org.springframework.mail.javamail.JavaMailSenderImpl.doSend(JavaMailSenderImpl.java:389)
at org.springframework.mail.javamail.JavaMailSenderImpl.send(JavaMailSenderImpl.java:306)
at org.springframework.mail.javamail.JavaMailSenderImpl.send(JavaMailSenderImpl.java:296)
at com.aa.meals.mail.MealsMailSenderBean.sendMail(MealsMailSenderBean.java:21)
at com.aa.common.log.TestMail.main(TestMail.java:14)
help my java is not allowing me to install it says the installer cannot proceed with the current internet settings
following is my java code error.
Exception in thread "main" java.net.UnknownHostException: ubaid.tk
could you help me.
cp –p mail.cf mail.cf.orig
#inet_interfaces = $myhostname, localhost
#inet_interfaces = $myhostname, localhost
Test connection from unix prompt
telnet pslab17 25
Connected to pslab17.
Escape character is '^]'.
220 pslab17.localdomain ESMTP Postfix
Connection closed by foreign host.
google "setting java options -D ipv4=true"
Please check for the port number as its already in use by another application , if yes, kill that process and restart the server.like
go to command prompt—>type netstat -ano | find "port number"
you will find list of applications using your port number.. then just type
taskkill /pid "pid of port no" /f
restart server then it should work..
Hello
I am getting java.net.SocketException: Network is down: listen failed exception
what may be the reason?
Hostname maps to multiple IP addresses and one of the IP address is down. Some network libraries automatically try a connection to second server while others need to have code in the application. nslookup hostname. $telnet hostname 25 needs to be replaced with $telnet ip-address 25
An important point to note is that if you are using alias e.g. DNS to connect to database or servers then you must remember that JVM can cache DNS value to avoid looking up again and again when a connection needs to be made. This is all ok and improves performance but also risky in the even to fail-over when DNS points to another server. There is a JVM option to configure this behavior e.g. how long to cache, cache or not etc, worth looking.
java.net.ConnectException: Connection timed out: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:351)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:213)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:200)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
at java.net.Socket.connect(Socket.java:529)
at java.net.Socket.connect(Socket.java:478)
at sun.net.NetworkClient.doConnect(NetworkClient.java:163)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:388)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:523)
at sun.net.www.http.HttpClient.(HttpClient.java:227)
at sun.net.www.http.HttpClient.New(HttpClient.java:300)
at sun.net.www.http.HttpClient.New(HttpClient.java:317)
at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:970)
at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:911)
at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:836)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1172)
at java.net.URL.openStream(URL.java:1010)
at com.lowagie.text.Image.getInstance(Unknown Source)
at com.lowagie.text.Image.getInstance(Unknown Source)
at jsp_servlet._health_ecard.__hlth_idcard._jspService(__hlth_idcard.java:217)
at weblogic.servlet.jsp.JspBase.service(JspBase.java:34)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227)
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:301)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:184)
at weblogic.servlet.internal.RequestDispatcherImpl.invokeServlet(RequestDispatcherImpl.java:526)
at weblogic.servlet.internal.RequestDispatcherImpl.forward(RequestDispatcherImpl.java:253)
at org.apache.struts.action.RequestProcessor.doForward(RequestProcessor.java:1078)
at org.apache.struts.action.RequestProcessor.processForwardConfig(RequestProcessor.java:396)
at com.allianz.weo.struts.WeoRequestProcessor.processForwardConfig(WeoRequestProcessor.java:141)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:232)
at com.allianz.weo.struts.WeoRequestProcessor.process(WeoRequestProcessor.java:37)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:449)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227)
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:301)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:184)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.wrapRun(WebAppServletContext.java:3729)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3696)
at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)
at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:120)
at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2273)
at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2179)
at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1490)
at weblogic.work.ExecuteThread.execute(ExecuteThread.java:256)
at weblogic.work.ExecuteThread.run(ExecuteThread.java:221)
org.openqa.selenium.WebDriverException: java.net.ConnectException: Failed to connect to localhost
@Unknown, check if your server or Java application is running or port is correct.
My javanet connection on scratch day
hello Lokesh, what does that mean? are you getting any error?
INLT3635@Thread[main,5,main]@1655277498232
com.freedomgroup.common.communicator.TFGHttpClient:
Connection refused: connect:
Connection refused: connect
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at com.freedomgroup.common.exception.TFGExceptionUtility.createThrowable(TFGExceptionUtility.java:328)
at com.freedomgroup.common.exception.TFGExceptionUtility.createSessionException(TFGExceptionUtility.java:239)
at com.freedomgroup.common.gui.request.TFGInvocationHandler.invokeService(TFGInvocationHandler.java:97)
at com.freedomgroup.common.gui.request.TFGInvocationHandler.invokeService(TFGInvocationHandler.java:239)
at com.freedomgroup.common.gui.request.TFGInvocationHandler.invoke(TFGInvocationHandler.java:157)
at com.sun.proxy.$Proxy0.getSystemDeploymentName(Unknown Source)
at com.freedomgroup.policystar.gui.util.TFGPolicyStarUtilities.getSystemDeploymentName(TFGPolicyStarUtilities.java:2460)
at com.freedomgroup.policystar.gui.base.TFGPolicyStarGUIRunner.main(TFGPolicyStarGUIRunner.java:425)
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: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:606)
at java.net.Socket.connect(Socket.java:555)
at java.net.Socket.(Socket.java:451)
at java.net.Socket.(Socket.java:303)
at org.apache.commons.httpclient.protocol.DefaultProtocolSocketFactory.createSocket(DefaultProtocolSocketFactory.java:80)
at org.apache.commons.httpclient.protocol.DefaultProtocolSocketFactory.createSocket(DefaultProtocolSocketFactory.java:122)
at org.apache.commons.httpclient.HttpConnection.open(HttpConnection.java:707)
at org.apache.commons.httpclient.MultiThreadedHttpConnectionManager$HttpConnectionAdapter.open(MultiThreadedHttpConnectionManager.java:1361)
at org.apache.commons.httpclient.HttpMethodDirector.executeWithRetry(HttpMethodDirector.java:387)
at org.apache.commons.httpclient.HttpMethodDirector.executeMethod(HttpMethodDirector.java:171)
at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:397)
at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:323)
at com.freedomgroup.common.communicator.TFGHttpClient.processRequest(TFGHttpClient.java:227)
at com.freedomgroup.common.communicator.TFGHttpRequestHandler.processRequest(TFGHttpRequestHandler.java:99)
at com.freedomgroup.common.gui.request.TFGInvocationHandler.invokeService(TFGInvocationHandler.java:79)
. 5 more
How can I help? did you checked if the server is up and running and whether you can connect to the server? If you are running your from home then make sure you check that VPN is connected to your office network as well.
Ошибка java.net.ConnectException: Connection refused – как исправить?
Ошибка java.net.ConnectException: Connection refused является одним из самых распространенных сетевых исключений в Java. Эта ошибка возникает, когда вы работаете с архитектурой клиент-сервер и пытаетесь установить TCP-соединение от клиента к серверу.
Соединение также происходит в случае RMI (удаленного вызова метода), потому что RMI также использует протокол TCP-IP. При написании кода клиентского сокета на Java вы всегда должны обеспечивать правильную обработку этого исключения.
В этом руководстве по Java вы узнаете, почему возникает исключение при отказе в соединении и как решить проблему.
Причины
Отказ в соединении – это явный случай, когда клиент пытается подключиться через порт TCP, но не может это сделать. Вот некоторые из возможных причин, почему это происходит:
- Клиент и Сервер, один или оба из них не находятся в сети.
Да, возможно, что они не подключены к локальной сети, Интернету или любой другой сети.
- Сервер не работает.
Вторая наиболее распространенная причина – сервер не работает. Вы можете использовать следующие сетевые команды, например, ping, чтобы проверить, работает ли сервер.
- Сервер работает, но не видит порт, к которому клиент пытается подключиться.
Это еще одна распространенная причина возникновения «java.net.ConnectException: соединение отклонено», когда сервер работает, но видит другой порт. Трудно разобраться в этом случае, пока вы не проверите конфигурацию.
- Брандмауэр запрещает комбинацию хост-порт.
Почти каждая корпоративная сеть защищена. Если вы подключаетесь к сети других компаний, вам нужно убедиться, что они разрешают друг другу IP-адрес и номер порта.
- Неверная комбинация хост-портов.
Проверьте последнюю конфигурацию на стороне клиента и сервера, чтобы избежать исключения отказа в соединении.
- Неверный протокол в строке подключения.
TCP является базовым протоколом для многих высокоуровневых протоколов, включая HTTP, RMI и другие. Нужно убедиться, что вы передаете правильный протокол, какой сервер ожидает.
Если вам интересно узнать больше об этом, то изучите книгу по сетевым технологиям, такую как Java Network Programming (4-е дополнение), написанную Гарольдом Эллиоттом Расти.
Как решить java.net.ConnectException: соединение отказано
Простое решение состоит в том, чтобы сначала выяснить фактическую причину исключения. Здесь важнее всего подход к поиску правильной причины и решения. Как только вы узнаете реальную причину, вам, возможно, даже не потребуется вносить какие-либо существенные изменения.
Вот несколько советов, которые могут помочь исправить ошибку java.net.ConnectException: Connection refused:
- Сначала попытайтесь пропинговать целевой хост, если хост способен пинговать, это означает, что клиент и сервер находятся в сети.
- Попробуйте подключиться к хосту и порту сервера, используя telnet. Если вы можете подключиться, значит что-то не так с вашим клиентским кодом. Кроме того, наблюдая за выводом telnet, вы узнаете, работает ли сервер или нет, или сервер отключает соединение.
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java.net.ConnectException – How to solve Connect Exception
In this example we are going to discuss about one of the most common exceptions you will come across when dealing with network programming in Java: ConnectException . ConnectException is a subclass of SocketException , and that alone reveals that it is meant to inform you about an error that occurred when you tried to create or access a socket. To be more specific, ConnectException is an exception that you will see in the client side of your application and it can emerge when a client fails to create a connection with a remote server socket.
1. A simple Client-Server program
Here is a very simple Client-Server program. It creates two threads. The first one, SimpleServer , opens a socket on the local machine on port 3333 . Then it waits for a connection to come in. When it finally receives a connection, it creates an input stream out of it, and simply reads one line of text from the client that was connected. The second thread, SimpleClient , attempts to connect to the server socket that SimpleServer opened. When it does so, it sends a line of text and that’s it.
As you can see, because I’m launching the two threads simultaneously, I’ve put a 3 second delay in SimpleClient for the client to wait before attempting to connect to the server socket, so as to give some time to server thread to open the server socket.
If you run the above program, after 3 seconds you will see something like this :
That means that the client, successfully connected to the server and achieved to transmit its text.
2. Simple cases of ConnectException
What happens if the client attempts to connect to localhost , not in port 3333 that the server listens, but instead in port 1234 . To test that I will simply change line:
And run the program again.After 3 seconds, here’s what happens:
So there, immediately, you have one occasion that can trigger a java.net.ConnectException . The reason is that you, obviously trying to access a port on localhost that is not open.
Other examples that also trigger a java.net.ConnectException follow the same pattern more or less: You are attempting to make a connection on a remote socket and that connection is refused. The reason it’s refused can vary. In the above example, I’m trying to access a port on the local machine that simply doesn’t exist.
Same thing happens:
If you want to try this make sure, you put a valid existing IP address (or else you will get an UnknownHostException ). But the point is that again, we are trying to connect to a specific server to a specific port, but that port doesn’t exist of the server.
Another trivial example is to simply not start the server thread and just let the client run. You can change the IP and port values in the client to be in the “correct” configuration : socket = new Socket(«localhost», 3333); .
But don’t start the server thread:
The same thing happens:
In this case the server was not running at all, even though the client used the correct configuration.
[Solved] java.net.ConnectException: Connection refused
Java is famous for networking applications. Java programmers have written socket programming for client server-based architecture. Most of the socket programming uses TCP-IP protocol for communication between client-server. Remote Method Invocation (RMI) also uses the TCP-IP protocol for communication. Sometime, it will generate java.net.ConnectException Connection refused exception for some communication channel error.
In this article, we will describe why this communication channel exception occurs in the first part, and in the second part, we will explain how to solve it.
1. Reasons for java.net.ConnectException
1. PORT or IP is incorrect: If PORT or IP is wrong, then the client will not be able to connect to the desired server. Then it will get this kind of exception.
2. Server is stopped: Suppose a server administration gave some IP address and PORT to you to access the server. But he stopped the server, but your client programs trying to access the server with administrator provided credentials, the client program will get the exception.
3. Protocol mismatch: We know that HTTP, RMI, Websocket, etc. uses TCP as the underlying protocol. HTTP request will start with http:// and RMI protocol starts with rmi// or WebSocket protocol start with ws://. If we request an HTTP request with rmi protocol, it will throw the java.net.ConnectException.
4. Server running in the different port: If server administrator provides you an IP and PORT but server running in a different port, it will give java.net.ConnectException Connection refused.
5. Server or client is not in the network: If the client or server is disconnected from the network, then the client will not be able to find out the server. When the client program will not be able to find out the server, we will get this exception.
6. Firewall Restriction: In the networking world, many malware or virus programs can affect the network or personal computer that is connected to the public network. The different organizations put a firewall to the network to prevent this unwanted attack of various harmful products. Some companies allow internal networks only. If your server programs run on this network and the client IP is not allowed in this network, it will get the exception java.net.ConnectException Connection refused.
2. How to Solve this Exception:
The client can connect with the server easily when
a. The server is running in the IP and PORT provided by the server administrator.
b. There is no restriction on the network.
c. The client and server are on the network.
We have to check the above things first before connecting to the server. We can test this in different ways.
1. We can check the IP and PORT are available for the client by using telnet.
For example, you can use this command to check IP and PORT are running or not.
2. We can check the IP is available for the client by pinging IP provided by the server administrator.
For example, you can ping with this command
You will get below result:
3. Practical Example:
1. When we try to connect a database server like MYSQL or Oracle, but IP or PORT is not running or not accessible, then we get the exception java.net.ConnectException.
2. When a mail server is not running the desired PORT or IP, we will get this kind of exception.
3. When an application running in a different PORT or IP, but the client tries to connect, we will get this exception.
Example with Java Code
If we execute the following command from the command line, we will get the desired exception