What are and used for?

Question

I was working on custom tag libraries and I was confused how the and tags are used in the TLD file to define a cus

Answer 1

The element defined in a TLD captures the dynamic behavior of an attribute. The value can be either true or false. A false value in the dynamic column means that only a static string value can be specified for the attribute. A true value means that a request-time attribute value can be specified. As defined in the JSP specification, a “request-time attribute value” can be either a Java expression, an EL expression, or a value set by a .

The element defines if the nesting attribute is required or optional. If not present then the default is "false", i.e the attribute is optional.