It sounds like you have Tomcat running, and it's listening on port 8080. If that's the case, then your go program will be unable to bind a listening socket on port 8080 at the same time. Either modify your go program to bind to a different port; or stop Tomcat before starting your go program; or modify the Tomcat config to bind to a different port, and restart it.
Note that you should have seen an error message from your go program telling you the problem. http.ListenAndServe returns an error - but unfortunately you threw that value away, so you see nothing.
Go doesn't have exceptions. It's up to you to put the error value returned by a function in a variable, and do something useful with it. e.g.
err := http.ListenAndServe(":8080",nil)
if err != nil {
fmt.Println(err)
}