Question: When I'm trying to set up a socket server, I've got an error message:

```
Exception in 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.<init>(ServerSocket.java:194)
    at java.net.ServerSocket.<init>(ServerSocket.java:106)
    at socketyserver.SocketyServer.main(SocketyServer.java:12)
Java Result: 1

```

Whole code is simplest as it can be:

```
public static void main(String[] args) throws UnknownHostException, IOException
{
    ServerSocket serverSocket;
    serverSocket = new ServerSocket(9999);
}

```

I'm 100% sure that my ports are forwarded, Windows Firewall is off. Nothing blocks port 9999. What else can go wrong?

Answer: 
It may be related to a **misconfiguration** in your `/etc/hosts`.
In my case, it was like this:
`192.168.1.11 localhost` instead of `127.0.0.1 localhost`
Just for others who may look at this answer in the hope of solving a similar problem, I got a similar message because my ip address changed.

```
java.net.BindException: Cannot assign requested address: bind
    at sun.nio.ch.Net.bind(Native Method)
    at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:126)
    at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:59)
    at org.eclipse.jetty.server.nio.SelectChannelConnector.open(SelectChannelConnector.java:182)
    at org.eclipse.jetty.server.AbstractConnector.doStart(AbstractConnector.java:311)
    at org.eclipse.jetty.server.nio.SelectChannelConnector.doStart(SelectChannelConnector.java:260)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59)
    at org.eclipse.jetty.server.Server.doStart(Server.java:273)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59)

```