Fixing Java.Net.Bindexception: Cannot Assign Requested Address: Jvm_Bind Inwards Tomcat, Jetty

Some of the most dreaded fault inward Java based customer server based application is networking related error, e.g. java.net.BindException: Cannot assign requested address: JVM_Bind. I conduct keep faced this issue, piece working alongside spider web servers similar Tomcat, Jetty, too Weblogic before, merely yesterday it came again, when 1 of my colleague faced this final result inward Windows. As presently equally Java programmers sees java.net.BindException, they come upward to determination that it's final result alongside two procedure listening on same port, too ofttimes mistook it for Java.net.BindException: Address already inward use: JVM_Bind:8080, which is slightly dissimilar than this.

If you lot await Java documentation for java.net.BindExcpetion, you lot volition uncovering this "Signals that an fault occurred piece attempting to bind a socket to a local address too port. Typically, the port is inward use, or the requested local address could non hold upward assigned."

It's the second part, which is to a greater extent than interesting inward representative of java.net.BindException: Cannot assign requested address: JVM_Bind.

When you lot kickoff a web server or application server, which typically head on a port e.g. Tomcat or Jetty listens on 8080 too 8084 for HTTP and HTTPS traffic, they bind a socket to a local address too port. If you lot hand them hostname e.g. localhost or devhost, too hence they used /etc/host inward both Windows too Linux to resolve domain cite into IP address, if this mapping is wrong than you lot volition instruct java.net.BindException: Cannot assign requested address: JVM_Bind.

This host to IP address mapping file tin hold upward constitute at C:\Windows\System32\Drivers\etc\hosts, where C:\Windows is  where you lot conduct keep installed windows operating system. If you lot await at this file, you lot volition meet it contains IP address too hostname equally shown below :

#127.0.0.1 localhost 192.168.52.1 localhost

If this mapping is changed too localhost cannot hold upward resolve to 192.168.52.1 too hence you lot volition instruct java.net.BindException: Cannot assign requested address: JVM_Bind. You tin essay past times next programme to reproduce this issue, remember, you lot ask admin rights to change /etc/host settings inward Windows.

import java.io.IOException; import java.net.ServerSocket;  public class ServerSocketTesting {      public static void main(String args[]) throws IOException {          ServerSocket server = new ServerSocket(8080);         System.out.println("Server is started, listening connections on port :8080 ");         server.accept();     } }

If your /etc/host mapping is wrong than you lot volition meet something like

Exception inward thread "main" java.net.BindException: Cannot assign requested address: JVM_Bind     at java.net.PlainSocketImpl.socketBind(Native Method)     at java.net.PlainSocketImpl.bind(PlainSocketImpl.java:383)     at java.net.ServerSocket.bind(ServerSocket.java:328)     at java.net.ServerSocket.(ServerSocket.java:194)     at java.net.ServerSocket.(ServerSocket.java:106)

Just, right the mapping, or add together 127.0.0.1 against localhost to resolve this issue.  That's all near how to laid upward java.net.BindException: Cannot assign requested address: JVM_Bind fault in Java based customer server application e.g. Minecraft, a pop game inward Java, which also communicate alongside server too other machines using TCP too sockets. It could  also hold upward hap when you lot are using spider web too application server similar Tomcat, Jetty or Weblogic as well. Next time, instead of thinking that 2 procedure is listening on same port, also mean value near hostname to IP address resolution final result too verify contents of /etc/host file inward both windows too Linux. Let me know if you lot are facing this final result too non able to resolve, pasting fault message too what you lot are trying to hit volition aid to solve your fault chop-chop too accurately.

How to resolve java.net.BindException: Cannot assign requested address: JVM_Bind inward Tomcat

If you lot are getting this final result inward Tomcat spider web server than opened upward your server.xml, which contains host too port information for Tomcat connectors. You tin uncovering server.xml inward place (Windows OS) C:\Program Files\Apache Software Foundation\Apache Tomcat 7.0.41\conf\server.xml. Now await for your connector, if you lot are using default settings too hence your connector volition await similar this :

 <Connector port="8080" protocol="HTTP/1.1"                connectionTimeout="20000"                redirectPort="8443" />

merely if you lot conduct keep modified it to include address="TestServer", too hence await for TestServer mapping inward /etc/hosts file. Try ping alongside the IP address too meet if it upward or not, you lot volition uncovering that it's incorrect. Just update alongside right IP too restart Tomcat.

Similarly, you lot tin resolve java.net.BindException: Cannot assign requested address: JVM_Bind inward Jetty or whatever other spider web server. Key affair is non to confuse this fault alongside address already inward purpose error.

All the best too allow me know if you lot seem upward similar issues.

Further Reading
The Complete Java MasterClass
Java Network Programming, (4th Addition) past times Harold, Elliotte Rusty
TCP/IP too Networking Fundamentals for information technology Pros

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