[HTTPCORE-420] Connections left open after HTTP synchronous server shutdown

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 4.4.3
• Fix Version/s: 4.4.5, 5.0-alpha2
• Component/s: HttpCore

Environment

java version "1.8.0_65"
Java(TM) SE Runtime Environment (build 1.8.0_65-b17)
Java HotSpot(TM) 64-Bit Server VM (build 25.65-b01, mixed mode)
Linux 3.0.101-0.47.71-default #1 SMP Thu Nov 12 12:22:22 UTC 2015 (b5b212e) x86_64 x86_64 x86_64 GNU/Linux

• External issue URL: http://stackoverflow.com/questions/36198302/proper-way-to-shutdown-apache-httpcomponents-blocking-http-server
• Assignee: Oleg Kalnichevski
• Reporter: Anton Krosnev
• Created: 29/Mar/16 15:13
• Updated: 21/Apr/16 10:44
• Resolved: 21/Apr/16 10:44

Description

I have observed the following problem on Linux with Apache HttpComponents 4.4.1 synchronous server: After calling server.shutdown(42, TimeUnit.MICROSECONDS), if there are Keep-alive connections opened (there is no request processing), these sockets are not closed. Only ServerSocket is closed:

netstat -aon | grep 58276

TCP 127.0.0.1:50658 127.0.0.1:58276 ESTABLISHED 18012

TCP 127.0.0.1:58276 127.0.0.1:50658 ESTABLISHED 18012

In attempt to start again HTTP server on the same port a BindingException is thrown:

Caused by: java.net.BindException: Address already in use
at java.net.PlainSocketImpl.socketBind(Native Method)
at java.net.PlainSocketImpl.socketBind(PlainSocketImpl.java:521)
at java.net.PlainSocketImpl.bind(PlainSocketImpl.java:414)
at java.net.ServerSocket.bind(ServerSocket.java:326)
at java.net.ServerSocket.<init>(ServerSocket.java:192)
at javax.net.DefaultServerSocketFactory.createServerSocket(ServerSocketFactory.java:170)
at org.apache.http.impl.bootstrap.HttpServer.start(HttpServer.java:116)

On Windows the behavior is the same , however there is no BindingException and the server starts process requests without any problems.

One can reproduce the problem using example code from https://github.com/anton-k11/apache-tests/tree/master

1. Start the server and the client.
2. Client will send several requests to the server.
   • Client will open 2 connections to the server.
3. After 1 min. the server will be shutdown.
   • Check the open connections on port 9090, the 2 connections between client and server are still open.
4. After 1 min. a new Server is started on the same port 9090.
   • On Linux this brakes with:

     java.net.BindException: Address already in use
     at java.net.PlainSocketImpl.socketBind(Native Method)
     at java.net.AbstractPlainSocketImpl.bind(AbstractPlainSocketImpl.java:387)
     at java.net.ServerSocket.bind(ServerSocket.java:375)
     at java.net.ServerSocket.<init>(ServerSocket.java:237)
     at javax.net.DefaultServerSocketFactory.createServerSocket(ServerSocketFactory.java:231)
     at org.apache.http.impl.bootstrap.HttpServer.start(HttpServer.java:116)
     at org.apache.http.examples.server.TestHttpServer.main(TestHttpServer.java:49)

   • On Windows this work just fine and the server is started successfully.