Java 2 Web Developer Certification Study Guide Natalie Levi

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1 SYBEX Index Java 2 Web Developer Certification Study Guide Natalie Levi Index Copyright 2002 SYBEX Inc., 1151 Marina Village Parkway, Alameda, CA World rights reserved. No part of this publication may be stored in a retrieval system, transmitted, or reproduced in any way, including but not limited to photocopy, photograph, magnetic or other record, without the prior agreement and written permission of the publisher. ISBN: SYBEX and the SYBEX logo are either registered trademarks or trademarks of SYBEX Inc. in the USA and other countries. TRADEMARKS: Sybex has attempted throughout this book to distinguish proprietary trademarks from descriptive terms by following the capitalization style used by the manufacturer. Copyrights and trademarks of all products and services listed or described herein are property of their respective owners and companies. All rules and laws pertaining to said copyrights and trademarks are inferred. This document may contain images, text, trademarks, logos, and/or other material owned by third parties. All rights reserved. Such material may not be copied, distributed, transmitted, or stored without the express, prior, written consent of the owner. The author and publisher have made their best efforts to prepare this book, and the content is based upon final release software whenever possible. Portions of the manuscript may be based upon pre-release versions supplied by software manufacturers. The author and the publisher make no representation or warranties of any kind with regard to the completeness or accuracy of the contents herein and accept no liability of any kind including but not limited to performance, merchantability, fitness for any particular purpose, or any losses or damages of any kind caused or alleged to be caused directly or indirectly from this book. Sybex Inc Marina Village Parkway Alameda, CA U.S.A. Phone:

2 Index Note to the reader: Page numbers in bold indicate primary discussions of a topic or the definition of a term. Page numbers in italics indicate illustrations. A absolute path, 368, 458 Accept header, 19, 20 access list, 238, 458 actions, about, creating custom JSP, custom, 359 defined, 332, 458 exam essentials for, 349 jsp:forward, jsp:getproperty, jsp:include, jsp:param, jsp:plugin, jsp:setproperty, 338, , 343, 444, 471 jsp:usebean, summary of attributes and subactions, 347 application object, 324, 458 application scope, 328, 458 application server, 415, 417, 458 applications, 323 architecture. See also Web client model J2EE about, 2 5 entity beans and, , 416, 462 illustrated, 4 session beans and, , 417, 471 Servlet model, 4 5, 5 web application directory structure, context, exam essentials for, 113 hierarchical layers of, location of client-viewed files in, /META-INF, 101, 466 WAR file, attackers, 234 attributes associated with servlet requests, defined, 458 defining and storing, error, 187 for include tag, 333 of INPUT tag, 7 11 JavaBean, beanname, 340 class, 340 id, 339 scope, 330, 330, , 471 type, 340 jsp:getproperty, 346 jsp:plugin mandatory, 335 optional, 336 jsp:setproperty, JSP custom tag, 364 notifying client session of changed, page directive, , 327, 468 parameters vs., 286 predefined request, 57 quotes around definitions of INPUT, 11 of Servlet model session object, 68 for ServletContext object, 129 setting object attributes within, 83 thread safety of, , 292 context, 271, request, 271, , 283 session, 271, , 285 auditing, declarative security, exam essentials for, 259 programmatic security, auth-constraint tag, 245, 261 authentication about, BASIC, 242, , 261

3 476 authorization client certificate CLIENT-CERT, , 252, 261 defined, 236, 458 DIGEST, , 250, 261 exam essentials for, 259, 261 FORM, , 248, 261 handling in web.xml file, overview, authorization about, defined, 236, 458 exam essentials for, 259 Automatic Code Generated DAO strategy, , 458 B base class, 393, 458 BASIC authentication, defined, 241 exam essentials for, 261 login-config element, , overview, , 258 security-constraint element, , , 260 security-role tags, 246 user name and password dialog box for, 242 Basic DAO strategy, Bean Managed Persistence (BMP), 431 beanname attribute of usebean action, 340 binary streams, 82 BingoServlet launching, sample listing for, using cookies with, using HttpSession object with, BMP (Bean Managed Persistence), 431 body of HTTP client requests, 21 of HTTP server response, 23 separating from header of HTTP client requests, 21 body content, , 459 BodyContent object flushing of, 392 handling, BodyTag interface, accessing enclosing writer, 387, 387 handling body content, life cycle of, 388, 388 sample listing of, BodyTagSupport class, , 392, , 397 boolean is Permanent() method, 185 Botanical Market scenario, Business Delegate layer, 438, 459 Business Delegate pattern, about, 414 advantages of, defined, 459 Delegate Adapter strategy, 439 delegate in application design, 438 Delegate Proxy strategy, 439 disadvantages of, 440 overview, , 449 Business Logic layer, 359 business objects, 431, 459 business services, 437, 438, 459 Business tier, 4 button attribute for INPUT tag, 11 C CA (certificate authority), 253, 459 case sensitivity of Java elements, 309 of request mapping, 98 CGI (Common Gateway Interface), 302 CHECKED attribute for INPUT tag, 8, 11, 459 CheckerServlet, class attribute of usebean action, 340 class variables, , 279, 280 defined, 271, 459 exam essentials for, 292 in SingleThreadModel, 289 thread safety of, 271, 272, 290 using, , 279, 280 CLIENT-CERT authentication, 242, certificate information, defined, 242 digital signatures, 252 exam essentials for, 261 overview, , 259 client certificate, 251, 459

4 clients data encoding for ServletRequest object 477 clients. See also Web client model client requests in HTTP, body of, 21 common header tags for, example of, 18 format of request line, header in, 19 in DIGEST process, 250, 250 linking of session objects and attributes to, 285 obtaining own local variables, 273, 273 reducing method calls with Value Object pattern, 418 clustering, 146 CMP (Container Managed Persistence), 431 Common Gateway Interface (CGI), 302 compile time, 333 conditional GET, 459 config object, 325, 459 Container Managed Persistence (CMP), 431 containers creating instance and registering listener classes before application requests, 133 multiple servlet instances per registered name, 288, 288 ServletConfig object, defined, 3, 460 distributed, implict and explicit mapping, 98 making application accessible by, 94 management of servlets in, 69 preventing web application deployment from same context path, 97 providing mapping information for, 107 registering session listeners to, 220 servlet container model, distributable environment, EEI mail application scenario, 145 exam essentials for, filters, HttpSession object, key terms for, 159 overview, review questions/answers, , ServletContext object, session ID transmittal determined by, 215 support for distributed, context, See also ServletContext object defined, 96, 460 overview of, 95 preventing web application deployment from same context path, 97 context attributes, defined, 271, , 460 exam essentials for, 292 thread safety of, 290 context object, 123, 460 context paths, 64, 460 mapping different paths with Context tag, 107 preventing web application deployment from same, 97 context-relative path, 367, 460 Context tag, 107 controller, 441, 441 controls, 9, 460 cookies defined, 66 67, 460 with OverviewServlet, retrieving and adding to response, 83 tracking sessions with, , 225 using with BingoServlet, custom actions. See JSP custom tags custom exception pages, custom tag mapping, 363 custom tags. See JSP custom tags D DAO objects, 430, 461 Data Access Object (DAO) pattern, about, 414 advantages of, Automatic Code Generated DAO strategy, Basic DAO strategy, DAO objects, 430 defined, 461 disadvantages of, 437 Factory for DAO strategy, overview, , data access objects (DAO), 430, 461 data encoding for ServletRequest object, 58 59

5 478 data integrity doxxx (...) request methods data integrity, , 259 instance locks and, , 275 synchronizing instance variable data, 275 using instance variable safely, 276 declarations, defined, 461 as implicit objects, overriding void jspinit() and void jspdestroy() methods, 307 overview of, 323 declarative security, 237, 461 default mapping, 98, 461 Delegate Adapter strategy, 439, 461 Delegate Proxy strategy, 439, 461 DELETE method, 31, 461 deployment descriptor. See also web.xml file basic, filters defining, known as web.xml file, 70, 103 sample, taglib directives in, using taglib element in, deployment descriptor tags, See also deployment descriptor basic servlet tags, for distributable environment, 148 exam essentials for, 114 for handling exceptions, 190 identifying element names for WebApp, 158 initialization parameters for servlet tag, mapping URL to servlet, , 109 MIME type mappings, security, , setting timeout flag with session-config tag, welcome file list, design patterns. See also Web tier design patterns about, 414 defined, 461 destroy() method, 79 digest, 250, 250, 461 DIGEST authentication, 242, , 250 creating a digest, 250, 250 defined, 242 exam essentials for, 261 nonce, 249, 250, 250, 467 overview, 259 process of, 250, 250 digital certificates, 253, 461 digital signature, 251, 252, 461 directives, about, , defined, 462 as implicit objects, 331 include, page, taglib, 322, defined, 322 in deployment descriptor, identifying on JSP page, 402 identifying tag use on JSP page, including in JSP page, directory structure, See also containers; context; web applications context, defined, 96 overview of, 95 preventing web application deployment from same context path, 97 exam essentials for, 113 hierarchical layers of, location of client-viewed files in, /META-INF, 101, 466 setting path for referencing ErrorServlet, 177 WAR file, /WEB-INF directory, 95 96, 98 99, 177 distributable environments, See also containers defined, 462 deployment descriptor tag for, 148 distributed containers, exam essentials for, overview of, distributed containers, doafterbody() method, 388, 389, 391, 404 dodelete(...) method, 50 doendtag() method, 388, 389, 391, 404 doinittag() method, 388 dostarttag() method, 387, 389, 404 doxxx (...) request methods, common features of, dodelete (...), 50 doget(...), dohead (...), 49 dooptions (...), dopost(...), 48

6 DTD (document type definition) files 479 doput(...), dotrace (...), 51 overview, DTD (document type definition), 105, 462 dynamic error pages, , , 462 E EEI mail application scenario, 145 EIS (Enterprise Information Systems), 3, 462 EIS tier illustrated, 4 J2EE tier design for Web, 415 EJBs (Enterprise Java Beans) defined, 415, 462 entity beans, , 416, 462 illustrated, 3 Multiple Value Objects strategy and, , 466 session beans, , 417, 471 encodeurl(...) method, , 226 end of servlet service, 79 entity beans, , 416, 462 Entity Inherits Value Object strategy, , 462 error-code tag, 176 error handling. See exception handling error pages, dynamic, forwarding requests with RequestDispatcher, , 180, 190 generating with senderror(...) method, , 189 setstatus(...) method, 174, 175 overview, 175 passing errors, sample listing dynamically generating, static, EVAL_BODY_BUFFERED, 404 EVAL_BODY_INCLUDE, 377, 404 event classes registering listener classes before application requests, 133 same listener tag used by all, 133 ServletContext object listener interfaces and, events, 462 exact mapping, 97, 462 exception handling, deployment descriptor tags for, 190 error pages, dynamic error pages, , 462 overview, 175 passing errors, , 180 static error pages, exam essentials, for HttpServlet request methods, 46 key terms, 190 logging messages, reporting messages, writing messages to log file, 181, 190 overview, problem notification, example of HTML output and servlet exception handling, senderror(...) method, , 189 setstatus(...) method, , 189 review questions/answers, , scenario planning for, servlet exceptions, exception pages, overview, ServletException class, throwing UnavailableException, exception object, 327, 463 exception pages, exceptions, 168, 463 Exotic Birds, Inc., scenario, 80 expressions defined, 463 exam essentials for, 323 as implicit object, 330 syntax and rules for writing, , 323 extensible, 463 Extensible Markup Language. See XML extension mapping, 97, 463 F factory, 433, 463 Factory for DAO strategy, , 463 files. See also WAR files; web.xml file index.html, JAR, 99,

7 480 filter-class tag HTML forms location of client-viewed, MANIFEST.MF, 101 minus sign in WAR file option tags, 100 naming of JSP, 304 signature, 101 WAR, writing error messages to log, 181 filter-class tag, 154 filter-mapping tag, 155 filter-name tag, filters, creating, defined, 463 defining deployment descriptor, life cycle of, , 151 overview, 150 sample listing of, 154 findancestorwithclass(...) method, firewalls, 241, 463 first-person penalty, 308, 463 flush tag for jsp:include, 333 FORM authentication custom authentication form, 248 defined, 241 exam essentials for, 261 form-login-config element, 249 overview, , 258 form-login-config element, 249 FORM tag, 6 7 forms, , 202, 463 forward action, , 464 forward(...) method servlet request dispatching and, transferring control of HTTP request to target resource, 281 duties of RequestDispatcher with, 84 G GenericServlet class, 181, 190 GET method defined, 464 exam essentials for, 33 generated for FORM tag when method unspecified, 7 identifying HttpServlet class methods for, 81 overview of, partial GET, 468 getbodycontent() method, 386 getenclosingwriter, , 387 getmaxinactiveinterval(...) method, getparameter (...) method, getproperty action, , 464 getrequestdispatcher() method, 75, 282 getservletcontext() method, 72 getservletname() method, 72 H hackers, 234, 464 HEAD method defined, 464 dohead (...) method of HEAD request, 49 exam essentials for, overview of, headers common tags for client requests, in HTTP client requests, 19 in HTTP server response, sample request for HttpServletRequest object, separating from body of HTTP client requests, 21 hello.jsp source code, hidden attribute for INPUT tag, 9 hidden comments, 310, 322, 464 hidden HTML values, , 202, 224, 464 HTML (Hypertext Markup Language), 5 16 defined, 464 FORM tag, 6 7 identifying request s parameters and header information, INPUT tag, 7 12 overview of, 5 query strings, 14 16, 469 SELECT tag, TEXTAREA tag, 14 URIs, 16, 473 when to use, 6 HTML forms defined, 463 storing client data between servlets for later use, , 202

8 HTML tags idempotent 481 HTML tags, 6 14 FORM, 6 7 INPUT, 7 12 SELECT, TEXTAREA, 14 HTTP (Hypertext Transfer Protocol), client request, closing connections after each request to server, 221 defined, GET method defined, 464 exam essentials for, 33 generated for FORM tag when method unspecified, 7 identifying HttpServlet class methods for, 81 overview of, partial GET, 468 identifying interface and methods to retrieve requests, redirecting requests to another URL, 82, 469 request methods, DELETE, 31 GET, HEAD, HTTP request/response communication, identifying HttpServlet class methods for, 81 OPTIONS, overview, POST, PUT, TRACE, 32 request/response communication for, server response, http-method tag, 245 HTTP request methods, DELETE, 31, 461 GET, HEAD, HTTP request/response communication, identifying HttpServlet class methods for, 81 OPTIONS, overview, POST, PUT, TRACE, 32 HttpServlet class, 81 HttpServlet request methods parameters and error handling for, 46 structure of methods, HttpServletRequest object, cookies, methods to generate session ID, 211 path elements, context path, 64 path info, 65, 468 servlet path, 64 65, 471 request methods for, 60 sample header request, security methods for, 239 HttpServletResponse object. See also HttpServlet Request object response methods for, HttpSession object, about, 67 assigning to client after request mapped to servlet, defined, 464 how sessions work, , 135, 136 HttpSessionActivationListener, , 156 HttpSessionAttributeListener, , 158 HttpSessionBindingEvent, 142 HttpSessionBindingListener, , 156, 219 HttpSessionEvent, 139 HttpSessionListener, , 156, methods for accessing or creating session, 137 overview, 156 using, with BingoServlet, with OverviewServlet, HttpSessionActivationListener, , 156 HttpSessionAttributeListener, , 158 HttpSessionBindingEvent, 142, 156 HttpSessionBindingListener, , 156, 219 HttpSessionEvent, 139, 156 HttpSessionListener, , 156, I id attribute of jsp:usebean, 339 idempotent, 47, 465

9 482 IllegalStateException Java applets IllegalStateException, 173 immutable, 276, 465 implicit objects, application object, 324 bolding of, 306 config object, 325 declarations, defined, 465 directive, 331 exam essentials for, 349 exception object, 327, 463 expressions, 330 out object, 326, 385, 467 page object, 327, 468 pagecontext object, , 401, 404, 468 request object, scope application, 328, 328 page, 328, 329 request, 329, 329 session, 330, 330 summarized, scriptlets, 330 session object, 326 include action, attribute types for, 333 defined, 465 limitations of included pages, 332 include directive, include(...) method including resource results inside response, 281 servlet request dispatching with, transferring duties of RequestDispatcher with, 84 indexed property, 465 index.html file as default welcome page for servlets, sample listing, , 206 inheritance hierarchy for javax.servlet.servlet interface, 307 init() method overriding no-argument, 70 problems preventing servlet from entering service, INPUT tag, 7 12 button attribute for, 11 checkbox attribute for, 11 hidden attribute for, 9 password attribute for, 9 radio attribute for, 12 reset attribute for, 10 submit attribute for, 9 10 text attribute for, 8 instance locks, , 275 instance variables, , 271, , 275 about, 273 accessing instance in turns, 275, 275 defined, 271, 465 exam essentials for, 292 sharing among accessing threads, 273, 275 SingleThreadModel and, 288 thread safety of, 271, 272, 276, 290 using, 274 int getunavailableseconds() method, 185 International Phone Card, Inc., scenario, 348 internationalization in ServletRequest object, 58 Internet Protocol (IP), 16 invalidating sessions, getmaxinactiveinterval(...) method for, invalidate(...) method for, 222, 225, 226 setmaxinactiveinterval(...) method for, , 225, 226 strategies for, with timeouts, 221, 225 IP (Internet Protocol), 16 isolation level, 428, 465 IterationTag interface, , 381 J J2EE (Java 2 Enterprise Edition). See also Web tier design patterns architectural overview of, 2 5 illustrated, 4 MVC implementation in, 442 server security, , 235 tier design for Web, 415 JAAS (Java Authentication and Authorization Service), 236 JAR (Java archive) files defined, 99, 465 WAR vs., 99, Jasper, 304 Java applets, 6

10 Java archive files JSP (Java Server Pages) 483 Java archive files. See JAR files Java Virtual Machine (JVM), 271 JavaBeans advantages of, 338, 341 attributes, defined, 338, 465 javax.servlet.error.exception attribute, 187 javax.servlet.error.message, 176 javax.servlet.error.status_code, 176 javax.servlet.filter interface, 152 javax.servlet.servlet interface, 307 javax.servlet.servletexception, 183 jsp:fallback, 337 jsp:forward, jsp:getproperty, , 464 jsp:include, jsp:param, jsp:plugin, jsp:fallback element for, 337 jsp:param element for, 337 mandatory attributes for, 335 optional attributes for, 336 jsp:setproperty, 338, , 343, 444, 471 jsp:usebean, attributes defining use of bean, beanname, 340 class, 340 id, 339 scope, type, 340 jsp:getproperty action, , 464 jsp:setproperty action, , 343 JSP (Java Server Pages), See also JSP custom tags; JSP model actions, about, jsp:forward, jsp:include, jsp:param, jsp:plugin, jsp:setproperty, 338, , 343, 444, 471 jsp:usebean, summary of attributes and subactions, 347 case-sensitivity of elements, 309 communicating with servlet with MVC pattern, converting to, 348 declarations as implicit objects, syntax and rules for writing, , 323 defined, 3, 465 directives, about, , defined, 462 as implicit objects, 331 include, page, , 327 taglib, 322 elements of, 309, exam essentials, 349 expressions exam essentials, 323 as implicit object, 330 syntax and rules for writing, , 323 hidden comments, 310, 322, 464 implicit objects, application object, 324 application scope, 328, 328 config object, 325 exception object, 327, 463 out object, 326, 385, 467 page object, 327, 468 page scope, 328, 329, 339, 468 pagecontext object, , 401, 404, 468 request object, request scope, 329, 329 scope of, session object, 326 session scope, 330, 330, , 471 JSP model, , 466 JSP life cycle, , 307, 308, 349 presentation layer separate from Java code, , 303, 304 servlet vs. JSP code, 4, 304 servlet vs. JSP design, 303 key terms, 350 overview, review questions/answers, , scriptlets defined, 313, 470 exam essentials for, 323 as implicit object, 330 statements within, syntax and rules for writing, , 323

11 484 JSP custom tags listener-class tag servlet communication to, syntax for elements in, JSP custom tags, BodyTag interface, accessing enclosing writer, 387, 387 life cycle of, 388, 388 sample listing of, common tag options, components required in, 360 custom tag mapping, 363 defined, 460 defining, exam essentials for, identifying in JSP page, 403 IterationTag interface, , 381 life cycle of, 381 sample listing, key terms, 404 overview, , review questions/answers, , sample listing of basic, 361 supplementary elements for, support classes, BodyTagSupport, , 392, TagExtraInfo, 392, , 400 TagSupport, 392, Tag handler, , 376 illustrated, 376 life cycle of, , 378 methods of, role of, 375 sample listing, taglib directives, defined, 322 in deployment descriptor, identifying in JSP page, 402 identifying tag use on JSP page, including in JSP page, TLD, creating, 362 defined, 362, 472 exam essentials for, 402 general tags for, 370 identifying descriptor elements and body content of, mapping to tag class, 363 optional tags, sample listing of, 369 WorldTalk, Inc., scenario, JSP model, defined, 466 JSP life cycle, , 307, 308 exam essentials for, 349 first-person penalty, 308, 463 illustrated, 308 JSP to servlet code for hello.jsp, servlet inheritance hierarchy, 307 presentation layer separate from Java code, , 303, 304 servlet vs. JSP code, 304 servlet vs. JSP design, 303 jspdestroy() method, 312 jspinit() method, 312 JVM (Java Virtual Machine), 271 K keys defined, 466 private, , 252, 469 public, 237, , 252, 469 L life cycle BodyTag interface, 388, 388 filters, , 151 of IterationTag interface, 381 JSP, , 307, 308 exam essentials for, 349 first-person penalty, 308, 463 illustrated, 308 JSP to servlet code for hello.jsp, servlet inheritance hierarchy, 307 servlets, defined, 471 end of service, 79 exam essentials for, loading and instantiating, request dispatching, request handling, of Tag interface, , 378 listener-class tag, 156

12 listener tag OverviewServlet.java 485 listener tag, 156 listeners defined, 466 in distributed environments, 150 for HttpSession object HttpSessionActivationListener, , 156 HttpSessionAttributeListener, , 158 HttpSessionBindingListener, , 156, 210 HttpSessionListener, , 156, registering to containers, 220 for ServletContext object, about, ServletContextAttributeEvent, ServletContextAttributeListener, 134, 156, 157, 158, 159 ServletContextEvent, ServletContextListener, , 156, 157, 158, 159 loading and instantiating servlets, local variables defined, 271 exam essentials for, 292 thread safety and, , 273, 290 log(...) method, 181, 190 logging messages, reporting messages, writing messages to log file, 181, 190 login-config tag, , M malicious code, , 259 MANIFEST.MF (manifest file), 101 manually rewriting URLs, , 206 mapping custom tag, 363 default, 98 exact, 97, 462 extension, 97 MIME type, path, 97 precedence of implict and explicit, 98 providing mapping information for containers, 107 URL to servlet, , 109 MAXLENGTH, 466 /META-INF directory, 101, 466 MIME (Multipurpose Internet Mail Extension) defined, 17, 467 MIME type mappings, mime-type tag, model, 441, 441. See also specific model by name Model View Controller (MVC) pattern, about, 414 advantages of, defined, 466 disadvantages of, 447 JSP to servlet, MVC component with scrollbar, 441 overview, , 441, 442, 449 servlet to JSP, Multiple Value Objects strategy, , 466 Multipurpose Internet Mail Extension (MIME), 17, , 467 multithreaded, 467 multithreaded servlets behavior of static variables in, 280 defined, 270 scenarios for handling multiple threads, single-threaded vs., , 292 mutable, 419, 467 MVC pattern. See Model View Controller pattern N NAME, 467 naming standards for JSP files, 304 nested tags, 364, , 387, 467 non-error, 174, 467 nonce, 249, 250, 250, 467 O option tags for WAR file, 100 OPTIONS method, 31 32, 50 51, 467 out object, 326, 385, 396, 404, 467 outer tags, 385 OverviewServlet.java sample listing, 206, using cookies with, using HttpSession object with,

13 486 packet sniffers reporting logged messages P packet sniffers, 241, 467 page attributes, 324, 468 page directive, , 327, 468 page object, 327, 468 page-relative path, , 468 page scope, 328, 329, 339, 468 page tag for jsp:include, 333 PageContext class, 380 pagecontext object, , 401, 404, 468 param action, , 468 param tag for jsp:include, 333 parameter variables, 272 parameters attributes vs., 286 for HttpServlet request methods, 46 init parameters for multiple instances of servlet, 280 for ServletRequest object, 53 56, 55, 56 thread-safe request, , 283 partial GET, 468 passing errors, password attribute for INPUT tag, 9 path patterns default mapping and, 98 exact mapping, 97, 462 extension mapping and, 97, 463 path mapping and, 97, 468 paths absolute, , 458 context-relative, , 460 manually rewriting URL, , 206 page-relative, , 468 path info, 65, 468 path mapping, 97, 468 path translations, request path elements, 65 request/response path for Servlet model, 52 servlet, setting for referencing ErrorServlet, 177 virtual, 66 permanently unavailable, 184, 468 plugin action about, defined, 468 mandatory attributes for, 335 optional attributes for, 336 POST method defined, 468 dopost(...) method with POST requests, 48 exam essentials for, identifying HttpServlet class methods for, 81 overview, prefix, 364, 469 prefix mapping, 366, 469 Presentation layer defined, 303, 469 separating from Business Logic layer with JSPs, 359 Presentation tier. See also Server tier; Web tier illustrated, 4 J2EE tier design for Web, 415 principal, 236, 469 private key, , 252, 469 problem notification, HTML output and servlet exception handling, senderror(...) method, , 189, 470 setstatus(...) method, , 189 programmatic security, , 469 public key, 237, , 252, 469 public void log() method, 181 PUT method, 29 30, 48 49, 469 Q query strings in HTML, 14 16, 469 R radio attribute for INPUT tag, 12 Real World scenarios Botanical Application, detailed session management, EEI mail application, 145 Exotic Birds, Inc. website, 80 for handling multiple threads, justifying robust system, planning for error handling, for security, WorldTalk, Inc., redirect URL, 82, 469 reporting logged messages,

14 req.getsession() method scopes 487 req.getsession() method, 211 request, 323 request attributes about, , 283 defined, 271, 281, 469 exam essentials for, 292 sample RequestDispatcher servlet, 282 thread safety of, 290 request dispatching of servlets, defined, 470 forward(...) method, include(...) method, request handling of servlets, request mapping, 98 request object about, , 325 defined, 470 HttpServletRequest object, cookies, methods to generate session ID, 211 path elements, request methods for, 60 sample header request, security methods for, 239 request/response path, 52 ServletRequest and ServletResponse interface, request path, request scope, 329, 329, 339, 470 request time, 333 RequestDispatcher accessing, defined, 470 forwarding request to error page, , 180, 190 include and forward methods transferring duties of, 84 thread safety of multithreaded requests, requests. See also HTTP request methods; responses accessing and setting attributes within, 83 attributes of servlet, forwarding to error page, , 180, 190 HTTP client, HTTP request/response communication, HttpServletRequest object, cookies, methods for, 60 methods to generate session ID, 211 path elements, request methods for, 60 sample header request, sample header request for, security methods for, 239 identifying interface and methods to retrieve, path elements, redirecting HTTP requests to another URL, 82, 469 servlets handling, request dispatching, request object for Servlet model, responses and, 4 5 reset attribute for INPUT tag, 10 response object, 470 responses. See also requests; server response for HTTP defined, 470 HTTP request/response communication, HTTP server, body, 23 example of, 22 header in, status line in, 22 HttpServletResponse object, servlet requests and responses, 4 5 setting HTTP response header and content type, 82 transmitting HTTP, 17 return variables, 272 review questions/answers exception handling, , Java Server Pages, , JSP custom tags, , security, , servlet container model, , Servlet model, 85 89, servlet web applications, , sessions, , thread safety, , Web client model, 35 39, Web tier design patterns, , role-based, 237, 470 roles, 236, S scope attribute of usebean action, scopes application, 340 defined, 122, 470

15 488 scriptlets servlet exceptions defining use of JavaBean, implicit objects, application, 328, 328 page, 328, 329 request, 329, 329 session, 330, 330 scriptlets defined, 313, 470 exam essentials for, 323 as implicit objects, 330 statements within, syntax and rules for writing, , 323 Secure Sockets Layer (SSL), security, auditing, authentication about, BASIC, , 242 CLIENT-CERT, , 252 DIGEST, , 250 FORM, , 248 overview, authorization, 236, 259, 458 data integrity, , 259 deployment descriptor tags, exam essentials, key terms, 262 malicious code, , 259 overview, , realworld scenario for, review questions/answers, , website attacks, 241, 260 security-constraint tag defining for BASIC authentication, exam essentials for, 260 restricting directory to administrator role, security-role tags, 246 SELECT tag, senderror(...) method, , 189, 470 Server tier, See also Presentation tier; Web tier entity bean transactions, , 416, 462 J2EE tier design for Web, 415 overview, 415 session beans, , 417, 471 servers application, 415, 417, 458 in DIGEST process, 250, 250 handling exceptions thrown to, 182 HTTP request/response communication, in J2EE model, 4 providing default directory for WAR file applications, 101 server response for HTTP, body in, 23 example of, 22 header in, status line in, 22 service(...) method, 52, 81 servlet container model, distributable environment, deployment descriptor tag for, 148 distributed containers, overview of, EEI mail application scenario, 145 exam essentials for, filters, creating, defined, 463 defining deployment descriptor, life cycle of, , 151 overview, 150 HttpSession object, how sessions work, , 135, 136 HttpSessionActivationListener, HttpSessionAttributeListener, HttpSessionBindingEvent, 142 HttpSessionBindingListener, , 156, 219 HttpSessionEvent, 139 HttpSessionListener, , 156, key terms for, 159 overview, review questions/answers, , ServletContext object, listener interfaces and event classes, methods and attributes, overview, servlet exceptions, custom error servlet, exception pages, HTML output and servlet exception handling, overview, permanently or temporarily unavailable, 184 ServletException class, throwing UnavailableException,

16 servlet-mapping tag ServletException class 489 servlet-mapping tag, 108 Servlet model, exam essentials for, key terms for, 84 methods for, common features of doxxx (...) methods, dodelete (...), 50 doget(...), dohead (...), 49 dooptions (...), dopost(...), 48 doput(...), dotrace (...), 51 overview, overview, 4 5, 5, 80 81, 471 request object, HttpServletRequest and HttpServletResponse interface, request/response path, 52 ServletRequest and ServletResponse interface, review questions/answers, 85 89, servlet life cycle, defined, 471 end of service, 79 init() method prevents servlet start, loading and instantiating, request dispatching, request handling, session object, servlet-name tag, 108 servlet path, 64 65, 471 servlet web applications, Botanical Application scenario, deployment descriptor tags, about web.xml file, 103 basic servlet tags, defining for filter, for distributable environment, 148 exam essentials for, 114 for handling exceptions, 190 identifying element names for WebApp, 158 initialization parameters for servlet tag, mapping URL to servlet, , 109 MIME type mappings, sample deployment descriptor, security, , setting timeout flag with session-config tag, welcome file list, directory structure, context, exam essentials for, 113 hierarchical layers of, location of client-viewed files in, /META-INF, 101, 466 setting path for referencing ErrorServlet, 177 WAR file, , 114 /WEB-INF, 95 96, elements of, 94 95, 113 exam essentials on, key terms, 114 notifying when session created or destroyed, overview, 113 review questions/answers, , ServletConfig object creation of, defined, 471 getservletcontext() method for, 72 getservletname() method for, 72 ServletContext object within application's, 123 ServletContext object, exam essentials for, 157, 158, 159 getrequestdispatcher() method of, 75, 282 listener interfaces and event classes, about, ServletContextAttributeEvent, ServletContextAttributeListener, 134, 156, 157, 158, 159 ServletContextEvent, ServletContextListener, , 156, 157, 158, 159 methods and attributes, overview, , 156 retrieving context attribute with, ServletContextAttributeEvent, ServletContextAttributeListener, 134, 156, 157, 158, 159 ServletContextEvent, ServletContextListener, , 156, 157, 158, 159 ServletException class about, defined, 471 UnavailableException subclass of,

17 490 ServletException object sessions ServletException object, 72 ServletRequest object attributes associated with requests, converting requests to, 52 data encoding for, internationalization in, 58 parameters for, 53 56, 55, 56 Request Dispatcher object and, request process for, 52 53, 53 ServletResponse object creation of by container, 52 request process for, 52 53, 53 servlets. See also servlet container model; Servlet model; servlet web application; thread safety communicating to JSP with MVC pattern, defined, 3, 470 flush() vs. close() methods for altering output stream, 151 handling exceptions, custom error servlet, exception pages, HTML output and servlet exception handling, overview, permanently or temporarily unavailable, 184 ServletException class, throwing UnavailableException, inheritance hierarchy for javax.servlet.servlet interface, 307 JSPs comparison of, 4 JSP component communication with, JSP vs. servlet code and design, 303, 304 life cycle of, defined, 471 end of service, 79 exam essentials for, loading and instantiating, request dispatching, request handling, processing with setstatus(...) method, 174 registering under multiple names, 277 requests and responses about, 4 5 HTTP request methods, 45 role of filter in, Servlet model, 4 5, 5 servlet tags basic deployment descriptor, initialization parameters for, single-threaded, single vs. multithreaded, , 292 timeout values for, 221 tracking for cookie with JSESSIONID, 212 translating scriptlets to, 313 unique init parameters for multiple instances of, 280 session attributes, , 285 defined, 271, 471 exam essentials for, 292 thread safety of, 290 session beans, , 417, 471 session-config tag, session ID encoding URL with, rewriting URL manually, , 206 transmittal between client and server determined by container, 215 URL rewriting and, session objects, 326, 471 creation of, , 136 function of, identifying interface and methods for retrieved, 225 invalidating, 226 linked to clients, 285 for Servlet model, tracking user transactions with, 136 session scope, 330, 330, , 471 SessionAttributeListener, exam essentials, 158 sessions, 135, , 136, See also HttpSession object; session ID; session objects creation of session object, , 136 defined, 135, 471 detailed session management scenario, exam essentials, HttpSession object, , about, 67 how sessions work, , 135, 136 HttpSessionActivationListener, HttpSessionAttributeListener, HttpSessionBindingEvent, 142 HttpSessionBindingListener, , 156, 219 HttpSessionEvent, 139

18 setbodycontent() method TagExtraInfo class 491 HttpSessionListener, , 156, identifying interface and methods for retrieved, 225 using, invalidating, getmaxinactiveinterval(...) method for, invalidate(...) method for, 222, 225, 226 setmaxinactiveinterval(...) method for, , 225, 226 strategies for, with timeouts, 221, 225 key terms, 226 notifying web applications when created or destroyed, overview, review questions/answers, , tracking, anonymous session tracking with URL rewriting, cookies for, , 225 function of session objects, storing client data using hidden HTML values, , 202, 224, 464 user transactions with session object, 136 using session data, 136, 136 setbodycontent() method, 386, 389 setmaxinactiveinterval(...) method, , 225, 226 setproperty action, 338, , 343, 444, 471 setstatus(...) method, , 189.sf (signature file), 101 single-threaded servlets multithreaded vs., , 292 overview, SingleThreadModel interface about, 290 class variables with, 289 defined, 288, 472 exam essentials for, 292 illustrated, 288 real world scenario for, 291 SIZE, 472 SKIP_BODY, 377, 378, 381, 404 SKIP_PAGE, 377, 404 SRC, 472 SSL (Secure Sockets Layer), stack trace defined, 181, 472 reporting message to client, statements within scriptlets, static error pages, , 472 static include, 318, 472 static variables, 147 status codes associating with static error pages, , 472 setting with setstatus(...) method, , 189 status line in HTTP server response, 22 submit attribute for INPUT tag, 9 10 suffix, 364, 472 support classes, BodyTagSupport, , 392, defined, 472 TagExtraInfo, 392, , 400 TagSupport, 392, synchronization defined, 472 in distributed environments, 147 of instance variable data, 275 thread safety of variables and attributes with, 290 Value Object pattern issues with, 428 synchronized, 274, 276, 472 syntax of custom tag, 365 for elements in JSP and XML, format of client request line, T tag extensions. See JSP custom tags Tag handler, , 376 illustrated, 376 life cycle of, , 378 methods of, role of tag interface, 375 sample listing, tag library descriptor. See TLD tag name, 364 tag value, 394, 472 TagExtraInfo class, 392, , 400

19 492 taglib directives type attribute of usebean action taglib directives, See also TLD defined, 322, 472 in deployment descriptor, identifying in JSP page, , 402 including in JSP page, tags. See also JSP custom tags; TLD; and specific tags by name deployment descriptor, basic servlet tags, for distributable environment, 148 exam essentials for, 114 for handling exceptions, 190 identifying element names for WebApp, 158 initialization parameters for servlet tag, mapping URL to servlet, , 109 MIME type mappings, security, , setting timeout flag with session-config tag, welcome file list, HTML, 6 14 FORM, 6 7 INPUT, 7 12 SELECT, TEXTAREA, 14 nested, 364, , 387, 467 outer, 385 page and param tags for jsp:include, 333 security-constraint, , , 260 security-role, 246 WAR file option, 100 TagSupport class, 392, TCP (Transmission Control Protocol), 16 temporarily unavailable, 184, 473 text including word wrapping for TEXTAREA tag, 14 text attribute for INPUT tag, 8 text stream acquisition, 82 TEXTAREA tag, 14 thread safety, in distributed environments, 147 exam essentials, 292 key terms, 292 overview, 291 passing unique instance to each caller and, 432 review questions/answers, , scenarios for handling multiple threads, single-threaded servlets, single vs. multithreaded servlets, , 292 variables and attributes, class variables, , 279, 280 context attributes, exam essentials for, 292 instance variables, 271, , 275, 465 local variables, , 273, 290 overview, 290 request attributes, , 283 session attributes, , 285 thread-safe variables, 272 Throwable object, 184, 187 timeouts invalidating sessions with, 221, 225 specifications for servlet, 221 strategies for invalidating sessions, unit of measure for servlet, 222 TLD (tag library descriptor), creating, 362 defined, 362, 472 defining action s body-content as empty, 378 exam essentials for, 402 general tags for, 370 mapping to tag class, 363 optional tags, sample listing of, 369 TLD resource path, 473 TRACE method about, 32 defined, 473 dotrace (...) method for TRACE requests, 51 traceroute, 473 tracking sessions, cookies for, , 225 function of session objects, storing client data using hidden HTML values, , 202, 224, 464 tracking user transactions with session object, 136 URL rewriting, , 225 defined, 202, 474 manual, , 206 methods for encoding URL, , 226 translation unit, 473 Transmission Control Protocol (TCP), 16 TYPE, 473 type attribute of usebean action, 340

20 UnavailableException subclass web applications 493 U UnavailableException subclass, , 473 Uniform Resource Identifiers (URIs), 16, 473 Uniform Resource Locators. See URLs updateable, 419, 473 Updateable (or Mutable) Value Object strategy, , 473 URIs (Uniform Resource Identifiers), 16, 473 url-pattern element, 244, 245 url-pattern tag, , 155 URLs (Uniform Resource Locators) defined, 473 mapping to servlet, , 109 redirecting HTTP requests to other, 82, 469 rewriting, , 225 defined, 202, 474 encoding links to, , 226 manual, , 206 uses of and elements in query strings, usebean action, attributes defining use of bean, beanname, 340 class, 340 id, 339 scope, type, 340 defined, 474 V VALUE, 474 Value Object Factory strategy, , 474 Value Object pattern, about, 414 advantages of, , 450 defined, 474 disadvantages of, Entity Inherits Value Object strategy, , 462 life cycle of, 419 Multiple Value Objects strategy, , 466 overview, , 448 Updateable (or Mutable) Value Object strategy, , 473 Value Object Factory strategy, , 474 value objects, 418, 423, 474 value objects, 418, 423, 474 VariableInfo object, , 400 variables, class, 271 exam essentials for, 292 immutable, 276 instance, , 271, , 275 about, 273 accessing instance in turns, 275, 275 defined, 271, 465 exam essentials for, 292 sharing among accessing threads, 273, 275 SingleThreadModel and, 288 thread safety of, 271, 272, 276, 290 using, 274 local, 271 static, view, 441, 441 void jspdestroy() method, 307 void jspinit() method, 307 voidprintstacktrace() method, 182 W WAR (Web archive) files, defined, 474 exam essentials for, 114 JAR files vs., 99, , 465 options for, 100 when to create, 101 web applications, See also thread safety authentication types BASIC, , 242, 258 CLIENT-CERT, , 252 DIGEST, , 250 FORM, , 248 overview, Botanical Application scenario, context objects as reference to, 123 defined, 474 deployment descriptor tags, about web.xml file, 103 basic servlet tags,

21 494 Web archive files Web tier design patterns defining for filter, for distributable environment, 148 exam essentials for, 114 for handling exceptions, 190 identifying element names for WebApp, 158 initialization parameters for servlet tag, mapping URL to servlet, , 109 MIME type mappings, sample deployment descriptor, for security, setting timeout flag with session-config tag, welcome file list, directory structure, context, exam essentials for, 113 hierarchical layers of, location of client-viewed files in, /META-INF, 101, 466 setting path for referencing ErrorServlet, 177 WAR file, , 114 /WEB-INF, 95 96, elements of, 94 95, 113 exam essentials on, key terms, 114 notifying when session created or destroyed, overview, 113 request dispatching, review questions/answers, secure, security principles and concerns, auditing, authentication and authorization, data integrity, , 259 malicious code, , 259 overview, website attacks, 241, 260 unnotified when each HTTP connection closed, 221 Web archive files. See WAR files Web client model, 2 41 architectural overview of J2EE, 2 5 exam essentials, HTML, 5 16 FORM tag, 6 7 INPUT tag, 7 12 overview of, 5 query strings, 14 16, 469 SELECT tag, TEXTAREA tag, 14 URIs, 16, 473 when to use, 6 HTTP, client request, DELETE method, 31, 461 GET method, HEAD method, OPTIONS method, 31 32, 50 51, 467 overview of, POST method, PUT method, 29 30, 48 49, 469 request methods, request/response communication for, server response, TRACE method, 32 key terms, 34 overview, review questions/answers, 35 39, web components, 3 /WEB-INF/classes, 99, 474 /WEB-INF directory about, 95 96, unable to directly reference files in, 177 /WEB-INF/lib/*.jar, 99, 474 /WEB-INF/web.xml, 474 web-resource-collection tag, , 260 web-resource-name tag, 238, 260 web servers, 3, 474 Web tier. See also Presentation tier; Server tier J2EE tier design for Web, 4, 415 Web tier design patterns, Business Delegate pattern, advantages of, Delegate Adapter strategy, 439 delegate in application design, 438 Delegate Proxy strategy, 439 disadvantages of, 440 overview, , 449 Data Access Object pattern, advantages of, Automatic Code Generated DAO strategy,