Your files are not under the JSP folder that's why it is not found. You have to go back again to 1 folder Try this:
<script src="../../Jquery/prettify.js"></script>
Or
Note the failing URL:
Failed ... http://localhost:8080/RetailSmart/jsp/Jquery/jquery.multiselect.css
Now examine one of your links:
<link href="../Jquery/jquery.multiselect.css" rel="stylesheet"/>
The "../" is shorthand for "The containing directory", or "Up one directory". This is a relative URL. At a guess, you have a file in /jsp/<somefolder>/ which contains the <link /> and <style /> elements.
I recommend using an absolute URL:
<link href="/RetailSmart/Jquery/jquery.multiselect.css" rel="stylesheet"/>
The reason for using an absolute url is that I'm guessing the links are contained in some common file. If you attempt to correct your relative pathing by adding a second "../", you may break any files contained in /jsp.
Hope this helps!
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Thanks!