title: How to change HTTP port that Play2 is listening on
body: <p>The documentation says:</p>
  
  <blockquote>
    <p>$ play start</p>
    
    <blockquote>
      <p>Note: the HTTP port can be set by passing -Dhttp.port system variable</p>
    </blockquote>
  </blockquote>
  
  <p>but I'm still hitting 9000 port taken error </p>
  
  <pre><code>$ /opt/play-2.0/play start -Dhttp.port=9001
  
  [info] Loading project definition from /my/path
  [info] Set current project to marmurka (in build file:/my/path/)
  
  (Starting server. Type Ctrl+D to exit logs, the server will remain in background)
  
  Play server process ID is 27505
  [info] play - Application started (Prod)
  Oops, cannot start the server.
  org.jboss.netty.channel.ChannelException: Failed to bind to: /0.0.0.0:9000
      at org.jboss.netty.bootstrap.ServerBootstrap.bind(ServerBootstrap.java:298)
      at play.core.server.NettyServer.&lt;init&gt;(NettyServer.scala:63)
      at play.core.server.NettyServer$.createServer(NettyServer.scala:131)
      at play.core.server.NettyServer$$anonfun$main$5.apply(NettyServer.scala:153)
      at play.core.server.NettyServer$$anonfun$main$5.apply(NettyServer.scala:152)
      at scala.Option.map(Option.scala:133)
      at play.core.server.NettyServer$.main(NettyServer.scala:152)
      at play.core.server.NettyServer.main(NettyServer.scala)
  Caused by: java.net.BindException: Address already in use
      at sun.nio.ch.Net.bind(Native Method)
      at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:137)
      at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:77)
      at org.jboss.netty.channel.socket.nio.NioServerSocketPipelineSink.bind(NioServerSocketPipelineSink.java:140)
      at     org.jboss.netty.channel.socket.nio.NioServerSocketPipelineSink.handleServerSocket(NioServerSocketPipelineSink.java:92)
      at org.jboss.netty.channel.socket.nio.NioServerSocketPipelineSink.eventSunk(NioServerSocketPipelineSink.java:66)
      at org.jboss.netty.channel.Channels.bind(Channels.java:462)
      at org.jboss.netty.channel.AbstractChannel.bind(AbstractChannel.java:186)
      at org.jboss.netty.bootstrap.ServerBootstrap$Binder.channelOpen(ServerBootstrap.java:343)
      at org.jboss.netty.channel.Channels.fireChannelOpen(Channels.java:170)
      at org.jboss.netty.channel.socket.nio.NioServerSocketChannel.&lt;init&gt;(NioServerSocketChannel.java:77)
      at org.jboss.netty.channel.socket.nio.NioServerSocketChannelFactory.newChannel(NioServerSocketChannelFactory.java:137)
      at org.jboss.netty.channel.socket.nio.NioServerSocketChannelFactory.newChannel(NioServerSocketChannelFactory.java:85)
      at org.jboss.netty.bootstrap.ServerBootstrap.bind(ServerBootstrap.java:277)
      ... 7 more
  </code></pre>