there is no such thing as javax.servlet.http.HttpSession.getAttribute()

lol yeah, if you have something like tail, monitor the log file, and replicate the error.

have you declared "stmt" anywhere?

JSP "should" be used for the interface, and you should leave the data retrieval, entry etc... to java services, but for a school project I really wouldn't worry...

To send the email, you can simply use mailto or use JavaMail if you more functionality.

This isn't a JSP issue, the &heart; isn't a standard special character so you need to make sure you page will handle the it. It will be an encoding issue of some sort. Find out which character-set...

You need to supply a lot more information...

e.g. what database are you connecting to?
what tables exist in this database?
etc...

Usually inserting data is more difficult than retrieving (I guess this depends on the nature of searches). So assuming you have a working database connection, it must be some simple error.

<link style="stylesheet" type="text/css" href="xxx.css" />

Goes in your head section.

You need to make sure your particular server allows for .jsp (i.e. has tomcat or something similar installed).

<%! %> tags are used for declarations. I recommend you don't use this for anything other than declaring your variables, and this is probably the cause of your issues.

Just use normal scriptlets <%...

the easiest solution is to just use scriptlets on the page the form is forwarded to. If you want to use jsp correctly, you should not use scriptlets but instead move this code to java classes.

Why do you need ajax?

This problem is most likely related more with your HTML & CSS than the actual JSP code.

You will need to add jars for activation and mail. Try mail.jar & activation.jar

I don't know what .jar the mysql driver is in. It shouldn't be that hard to find with a google. The .jar file goes into your web app directory under "WEB-INF\lib".

Unable to find a javac compiler;
Perhaps JAVA_HOME does not point to the JDK

Do you have JDK installed too? Make sure you let tomcat know where your java compiler is located.

Make sure you have "com.mysql.jdbc.Driver" in your web application. It will be contained in a .jar and it needs to go with your other java libraries you use.

Do you have java installed? If so check your path variables.

There is no need for 2 threads with the same question. If you are unsure as to how to do col4 + col5 that is a bit of a worry. Remember you are using JSP (i.e. java).

Well you can do arithmetic within the sql queries if you like, but seeing as though you already query for col1~3 just store them into int variables. I think your result set will save Strings, so use...

Yeah, well if you want experience, why not just start building something for yourself? That would probably interest you more than suggestions from others.

Are you after like a full on paying project? or something as a hobby?

1. Learn English
2. Learn Java
3. Do your project

This is really an outrages thread. Even if somebody wanted to help you, we have absolutely nothing to base it off... Hotel Management is a broad subject (I assume).

Have you tried this in SQL, because you are trying to access a variable within a string without catenation (spelling?).