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Still have Eclipse EE 404 on Mac after following advice on this issue

First of all, I am aware that there are other questions regarding Tomcat, Eclipse, and the infamous 404 error. However, none of them manages to resolve the issue. I have spent well over 24 hours on this issue.
To save time, when I configured everything (including Tomcat, and creating a server in Eclipse), I:
• Changed the server location from "workspace metadata" to its correct location by using the "Switch Location" button located in the server's Properties window.
• I chose the "Use Tomcat Installation" option in Server Locations, and saved the choice I made.
In both cases, I restarted the server. If you're curious as to what app I'm currently working on, it's a simple Hello World app, found at: http://theopentutorials.com/examples/java-ee/servlet/how-to-create-a-servlet-with-eclipse-and-tomcat/
• I have included the Java file in the "welcome file" list inside web.xml.
Lastly, out of curiosity, why does the Eclipse browser only go to the project directory, and not the servlet itself? (If I add on the servlet name, then "Hello World" appears).
• Yes, if I enter "http://localhost:8080", the default Tomcat page appears, so no issues there.
Can anyone clue me in, as to why I am still getting 404s after all this, and following advice that has been marked as "Accepted" here at SO, such as the following:
HTTP Status 404 - The requested resource (/) is not available
Thanks in advance for any help, it is greatly appreciated.

The error 404 may occur because of large amount of different reasons. In order to resolve that, you should check your tomcat log file out first. It contains by the path:
%PATH_TO_WORKSPACE%\.metadata\.plugins\org.eclipse.wst.server.core\tmp%SERVER_NUMBER%\
logs
Usually it contains some stacktraces which discribes the problem. If not, then you should check your deployed application out there:
%PATH_TO_WORKSPACE%\.metadata\.plugins\org.eclipse.wst.server.core\
tmp%SERVER_NUMBER%\___YOUR_APP____
It might happen that your application was not deployed correctly by eclipse plugin (happens very often) and you should try this:
Project --> clean
'Right click on your server' --> clean
Or just remove your webapp from the directory I mentioned erlier and redeploy it from scratch.

There is something basic you need to understand regarding using tomcat(or application server for that matter). There is a slight difference between using from Eclipse and using from outside
Using From within Eclipse
What happens here is that Eclipse (by default) uses a copy of your tomcat installation and places it in its metadata workplace. This secondary tomcat is used by Eclipse for all deployments, re-deployments and all. Keep in mind that this is not your original copy of tomcat installation.
The difference in this tomcat installation is that is actually a minimal server, meaning that although it has all the deployment capabilities, it does not have some of the extra features that come with the tomcat installation and one main feature is the tomcat's homepage (the only reason why people out there get the infamous 404 resource not found when they try to run-on-server their application).
Workaround
Although not an issue (nor a bug from the Apache's end), you can still view your application by changing the URL to your application's url, homepage or no homepage ! All you have to do is change the url from http://localhost:8080 to http://localhost:8080/yourApplicationName and voila , the default page of your application will be shown that you mentioned in the welcome-page-list. Keep note that if you didn't specify a default page in your web.xml, you will again wind up with, yet again, the dreaded 404 resource not found page. The reason is that Tomcat has found your application, but it doesn't know what to do at the root context of your application. You can either map your servlet to the root of the application (that way it will always run at http://localhost:8080/yourApplicationName) or you can change the URL to the url-pattern that you mapped with the servlet in the web.xml, it must be something like http://localhost:8080/myApplicationName/myServletMappingPattern

Avoid project's directory - Java EE app

I am writing and small app using Java EE. I am using Apache Tomcat v 7 and Eclipse as IDE. When I Run the project (Run on server) I get :
http://127.0.0.1:8080/java-web/lis
(That's fine)
But I don't know If there is some way to rewrite the [java-web] dir just to get :
http://my-local-app.dev/list
I suppose there is some way like in Apache Server using confing files and enabling
the mod_rewrite.
I'll apreciate your help. Thanks

In short: All of the pieces you want to change are components of your deployment environment. Unless you have a specific need to override them, it's usually easiest during development to use the URLs that are a little less pretty.
If you do want to alter them, you need to familiarize yourself with what the various parts of an HTTP URL mean. What you have in your test environment is this:
http:// 127.0.0.1:8080/java-web/list
protocol host port path
You could insert an entry into your hosts file listing my-local-app.dev at 127.0.0.1, but that would not change the port or the path.
The port is determined when Tomcat starts up and is 8080 by default. The general port for HTTP is 80, but specific permission is required to bind to ports below 1024. On Linux, the authbind package makes this pretty easy; on Windows, the necessary steps will depend on your version and configuration (e.g., if you have a Group Policy).
In Tomcat, Web applications are prefixed with their names in the path; it looks like your (hypothetical?) application is named java-web.war. You can install an application as the "root application", but this requires a little bit more configuration and is generally skipped in development.
All of this can indeed also be done using something like mod_rewrite, but that seems like overkill to have slightly prettier URLs for your dev machine.

If you want your application to respond to the my-local-app.dev, you need to purchase the "my-local-app.dev" domain and get a Java web hotel running on it.
If your web application is named "java-web" and you do not want the URL to reflect that, you need to tell Tomcat that you want your application deployed at the ROOT location where the name of the web application is not present in the URL. This is typically done in the deployment stage but unfortunately there is no standard location to say this for WAR files so this is vendor dependent. For example does Glassfish use an extra XML file in your deployment.
I believe Tomcat supports this for ROOT.war files. If not, you probably needs to set the META-INF/context.xml file. See https://tomcat.apache.org/tomcat-7.0-doc/config/context.html for details on what to put in this file - especially the context path.

Easiest way to deploy web app to Apache Tomcat

I'm trying to deploy my first servlet to my server. There are, of course, many tutorials online. But most of them are very detailed and complicated, and I only need to deploy a few simply servlets to this server.
I found what I think to be the shortest method of deployment: Deployment on Tomcat Startup. I moved my .WAR file (FirstProject.war) into $CATALINA_BASE/webapps folder, but when trying to access it (ServerIP/FirstProject) I get the "The requested resource is not available." error.
Is there anything I forgot in the process of deployment?
I know that deployOnStartup has to be set to true, but I didn't change anything with the server's hosts, so the current host is localhost. I didn't change its settings, so deployOnStartup should be true (It's said that true is the default).
What am I missing?

You are using easiest way but I don't know what you are missing. Here what I would suggest is run your server and access through localhost:8080 then click manage app then enter username and password then you can deploy your war.
If you have any query post command.

Even i used to face this problem while deploying my first web application on Jboss and Apache ..
Even though your code is working properly with all your servlet mappings and paths using in your content files ...some times they kick back in real time environment ..So we have to know the proper deployment folder structure and accordingly we have to change our paths in the code
what i am concluding is check the below lines of code
Examples, assuming root is http://foo.com/site/
Absolute path, no matter where we are on the site
/foo.html
will refer to http://foo.com/site/foo.html
Relative path, assuming the containing link is located in http://foo.com/site/part1/bar.html
../part2/quux.html
will refer to http://foo.com/site/part2/quux.html
or
part2/blue.html
will refer to http://foo.com/site/part1/part2/blue.html

An address of a website deployed using Tomcat and Eclipse

I'm trying to run a website using Tomcat and Eclipse. I created a Dynamic Web Project, I configured web.xml file and I also used Maven. In a directory src/main/webapp I put an index.html file. I also made a simple REST service in the same project. So this REST service is working for me (for example, when I put "http://localhost:8080/RESTfulService/rest/item" in an address bar. But what is the address that I should write to get an access to a website I put in a webapp folder? I thought "http://localhost:8080/RESTfulService/" should be working, but it's not.

From what i understand of your setup, try "http://localhost:8080/index.html". Do you have a context path called 'RESTfulService' setup?
Do you have a context element listed in your server.xml? If so, what does it say?

how to make my files present in a tomcat server to the browser

I have installed Tomcat 5.0 in order to execute a web application. How can I show my files which are present in Tomcat to the web browser? I tried http://hostname:8080/myfolder/login.html, but I can't see the files.
One more thing I know about JDBC and other database connectivity and I have developed a HTML page. How can I let a button in the page execute the code written in a Servlet and perform validations?

The simplest thing is to add to the root webapp. That is webapps/ROOT. Any file you put in there will be served unless you change the default configuration.
You should read about the details, of course.

I have installed Tomcat 5.0 in order to execute a web application.
First of all, why are you using the ancient (8 year old) Tomcat 5.0? If you can, rather grab the latest one, Tomcat 6.0.
How can I show my files which are present in Tomcat to the web browser? I tried http://hostname:8080/myfolder/login.html, but I can't see the files.
Is myfolder the context name or just a folder in your webcontent? If it's a context name, then you need to ensure that it's properly deployed. You can find details in the server logs in the /logs folder. If it is a folder in your webcontent and the webapplication is thus supposedly to be the "root" application, then you need to ensure that it's deployed as ROOT.
To learn more about using Tomcat, go through the documentation.
One more thing I know about JDBC and other database connectivity and I have developed a HTML page. How can I let a button in the page execute the code written in a Servlet and perform validations?
To the point, just create a class which extends HttpServlet, implement the doPost() method, define the servlet in web.xml and let the action attribute of the HTML <form> element point to an URL which is covered by the url-pattern of the servlet mapping in the web.xml.
As the question is pretty broad, I have the impression that you haven't learned in any way how to work with Tomcat and JSP/Servlets. I would strongly recommend to go through those tutorials to familarize yourself with JSP/Servlet on Tomcat and Eclipse (an IDE) first: Beginning and Intermediate-Level Servlet, JSP, and JDBC Tutorials

Tomcat is not a web server like, say, Apache. It's a servlet container. You can not just move file in a subfolder which seem to be what you did. You need to pack your web application in a .war and deploy it.
The URL should rather be http://host:8080/webapp/subfolder/login.jsp
Without much information it's hard to help. Please edit your question and describe what you've done so far.