The directive elements - specify information about the page itself that remains the same between requests--for example, if session tracking is required or not, buffering requirements, and the name of a page that should be used to report errors, if any.

• <%@ page ... %>

Legal attributes, with default values in bold, are:
import="package.class" or import="package.class1,...,package.classN". This lets you specify what packages should be imported. For example:
<%@ page import="java.util.*" %>
The import attribute is the only one that is allowed to appear multiple times.
contentType="MIME-Type" or
contentType="MIME-Type; charset=Character-Set"
This specifies the MIME type of the output. The default is text/html. For example, the directive
<%@ page contentType="text/plain" %>
has the same effect as the scriptlet
<% response.setContentType("text/plain"); %>

• isThreadSafe="true|false". A value of true (the default) indicates normal servlet processing, where multiple requests can be processed simultaneously with a single servlet instance, under the assumption that the author synchronized access to instance variables. A value of false indicates that the servlet should implement SingleThreadModel, with requests either delivered serially or with simultaneous requests being given separate servlet instances.
• session="true|false". A value of true (the default) indicates that the predefined variable session (of type HttpSession) should be bound to the existing session if one exists, otherwise a new session should be created and bound to it. A value of false indicates that no sessions will be used, and attempts to access the variable session will result in errors at the time the JSP page is translated into a servlet.
• buffer="sizekb|none". This specifies the buffer size for the JspWriter out. The default is server-specific, but must be at least 8kb.
• autoflush="true|false". A value of true, the default, indicates that the buffer should be flushed when it is full. A value of false, rarely used, indicates that an exception should be thrown when the buffer overflows. A value of false is illegal when also using buffer="none".
• extends="package.class". This indicates the superclass of servlet that will be generated. Use this with extreme caution, since the server may be using a custom superclass already.
• info="message". This defines a string that can be retrieved via the getServletInfo method.
• errorPage="url". This specifies a JSP page that should process any Throwables thrown but not caught in the current page.
• isErrorPage="true|false". This indicates whether or not the current page can act as the error page for another JSP page. The default is false.
• language="java". At some point, this is intended to specify the underlying language being used. For now, don't bother with this since java is both the default and the only legal choice.Defines page-dependent attributes, such as session tracking, error page, and buffering requirements

 

• <%@ include ... %>       

A file on the local system to be included when the JSP page is translated into a servlet.

• <%@ taglib ... %>           

Declares a tag library, containing custom actions, that is used in the page

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