Selenium: Invalid “already running” error when starting server

Question

I am trying to get the Selenium server up and running. However, when I type:

java -jar selenium-server-standalone-2.0b3.jar

I get an Exception

Answer 1

lsof returned no results in my case.

On a Ubuntu machine I had to do the following:

sudo netstat -tapen | grep ":4444 "

Reply was like:

tcp6       0      0 XXXXXXXXX:4444       :::*                    LISTEN      107        31526       **10479**/java

And to kill the Selenium server process identified (in my case) with 10479

sudo kill 10479