• In GET your entire form submission can be encapsulated in one URL, like a hyperlink. 
• query length is limited to 255 characters, not secure, faster, quick and easy. 
• The data is submitted as part of URL.

• In POST data is submitted inside body of the HTTP request. 
• The data is not visible on the URL and it is more secure

• Custom tags and beans accomplish the same goals -- encapsulating complex behavior into simple and accessible forms. 
• There are several differences:
• Custom tags can manipulate JSP content; beans cannot. 
• Complex operations can be reduced to a significantly simpler form with custom tags than with beans. 
• Custom tags require quite a bit more work to set up than do beans. 
• Custom tags usually define relatively self-contained behavior, whereas beans are often defined in one servlet and used in a different servlet or JSP page. 
• Custom tags are available only in JSP 1.1 and later, but beans can be used in all JSP 1.x versions.

• Custom JSP tag is a tag you defined. 
• You define how a tag, its attributes and its body are interpreted, and then group your tags into collections called tag libraries that can be used in any number of JSP files. 
• To use custom JSP tags, you need to define three separate components: 
• the tag handler class that defines the tag's behavior ,
• the tag library descriptor file that maps the XML element names to the tag implementations and
• the JSP file that uses the tag library

• JSP is used mainly for presentation only. 
• JSP can only be HttpServlet that means the only supported protocol in JSP is HTTP. 
• But a servlet can support any protocol like HTTP, FTP, SMTP etc.

• An HTML element starts with a start tag / opening tag
• An HTML element ends with an end tag / closing tag
• The element content is everything between the start and the end tag
• Some HTML elements have empty content
• Empty elements are closed in the start tag
• Most HTML elements can have attributes

Example