Where to mention port while giving hit to server?
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I have one small doubt and may be silly but I want to clear the doubt.

Say I have server computer in which I have tomcat and apache server running.

I can now access the admin page using 
"http://localhost:8080/" = Tomcat for java
"http://localhost/"      = Apache Server for php pages
 
So now when I access the url like 
http://www.abc.com/Construction/index.html
so it will go and hit which application ie apache or tomcat when both are having index.html page in it.

In short where we use to mention port?
http://www.abc.com/ in this url where is the application port mentioned also how do http protocol port 80 will come in picture in this?


Please clear my doubt.

Thanks