1.If the processID is different,kill one of the processes。

2.If the processID is the same,check the tomcat workspace---webapps&ROOT。

Normally we put the jenkins.war into the webapps then will exist a file folder

named jenkins after tomcat started successfully.if you put * of the jenkins folder

into ROOT folder,then you can visit jenkins by http://ip:port/ or

http://ip:prot/jenkins.And also you will hit the problem like this。

My way is delete the ROOT folder。IF you want visit the jenkins by

http://ip:port without the postfix,you can edit the /conf/server.xml and

add Context parameter.Good luck!