JAX-WS Web Service Fundamentals
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Questions and Answers

What is the purpose of the sun-jaxws.xml file in a JAX-WS web service?

  • It specifies the implementation class for the web service.
  • It maps the web service's methods to their corresponding operations.
  • It configures the web service's security settings.
  • It defines the endpoint for the web service. (correct)

    • Which annotation is used to define a method in a JAX-WS web service interface?

  • `@Service`
  • `@WebService`
  • `@Endpoint`
  • `@WebMethod` (correct)

    • What is the role of the WSServlet class in a JAX-WS web service deployment?

  • It determines the web service's endpoint URL.
  • It provides the entry point for the web service. (correct)
  • It marshals and unmarshals SOAP messages.
  • It handles the communication between the client and the server.

    • In a JAX-WS RPC style web service, how is the communication between the client and the server typically performed?

    <p>Via a service port defined by a QName. (B)</p> Signup and view all the answers

    Which of the following is a benefit of using the JAX-WS RPC style for web services?

    <p>It offers a more straightforward implementation compared to document style. (D)</p> Signup and view all the answers

    What is the purpose of marshalling in the context of JAX-WS web services?

    <p>It converts Java objects to XML representations for transmission. (D)</p> Signup and view all the answers

    What is the role of the @WebService annotation in a JAX-WS web service?

    <p>It marks a class as a web service implementation. (A)</p> Signup and view all the answers

    Which of the following options is a reference implementation of JAX-WS?

    <p>Glassfish Metro (B)</p> Signup and view all the answers

    What is the primary function of the Endpoint.publish() method in the JAX-WS API?

    <p>It deploys a web service implementation to a specific URL. (C)</p> Signup and view all the answers

    How can you access the WSDL document for a deployed JAX-WS web service using the RPC style?

    <p>By appending '?wsdl' to the web service's endpoint URL. (C)</p> Signup and view all the answers

    What is the primary purpose of JAXB in the given example?

    <p>To convert Java objects to XML and vice versa (A)</p> Signup and view all the answers

    Which HTTP method is used to create a new resource according to the provided web services information?

    <p>POST (A)</p> Signup and view all the answers

    What is the purpose of the JAXBContext in the context of the given JAXB example?

    <p>To provide an entry point for JAXB functionalities (B)</p> Signup and view all the answers

    In the context of web services, what does SOAP stand for?

    <p>Simple Object Access Protocol (C)</p> Signup and view all the answers

    What is an envelope structure in SOAP?

    <p>The wrapping or framing for a SOAP message (B)</p> Signup and view all the answers

    What kind of data communication does web services typically utilize?

    <p>XML-based messages (C)</p> Signup and view all the answers

    What does the marshalling process in JAXB do specifically?

    <p>It transforms a Java object into an XML representation (B)</p> Signup and view all the answers

    Which approach does JAX-WS extend according to the information provided?

    <p>JAX-RPC 1.0 (C)</p> Signup and view all the answers

    What is the primary function of the SOAPHandler interface?

    <p>To handle messages and determine whether the chain may continue. (D)</p> Signup and view all the answers

    Which annotation is used to specify the XML file for handler mapping in a JAX-WS service?

    <p>@HandlerChain (C)</p> Signup and view all the answers

    What are the main components of RMI in Java?

    <p>Remote method invocation and client/server architecture. (D)</p> Signup and view all the answers

    What is the purpose of the Java Remote Method Protocol (JRMP)?

    <p>To define a proprietary protocol for remote method calls. (D)</p> Signup and view all the answers

    Which of the following statements about IIOP is true?

    <p>IIOP is CORBA’s communication protocol that operates over TCP/IP. (D)</p> Signup and view all the answers

    What is a key benefit of using RMI in distributed Java applications?

    <p>It enables separate JVMs to call methods on each other seamlessly. (C)</p> Signup and view all the answers

    What does the @WebMethod annotation signify in a JAX-WS service?

    <p>The method can be accessed as a web service operation. (C)</p> Signup and view all the answers

    Which protocol did RMI adopt later for enhanced interoperability?

    <p>IIOP (B)</p> Signup and view all the answers

    In what context is the MacAddressValidatorHandler referenced?

    <p>As an example of a server-side handler. (B)</p> Signup and view all the answers

    What is the default setting for the RMI property java.rmi.server.useCodebaseOnly as of JDK 7 Update 21?

    <p>True (C)</p> Signup and view all the answers

    What does the RMI Naming method 'Lookup' do?

    <p>Returns a reference to a remote object (A)</p> Signup and view all the answers

    In the provided server implementation, which class is used to allow a remote object to be accessed?

    <p>UnicastRemoteObject (D)</p> Signup and view all the answers

    What is the primary function of the 'Rebind' method in RMI naming?

    <p>It replaces an existing binding with a new one (A)</p> Signup and view all the answers

    How do clients connect to the RMI registry in the provided client implementation example?

    <p>Using an IP address and port (B)</p> Signup and view all the answers

    Which method is used to initialize the RMI security manager?

    <p>System.setSecurityManager() (B)</p> Signup and view all the answers

    What does the exception RemoteException signify in RMI communication?

    <p>Issues with networking or remote communication (A)</p> Signup and view all the answers

    What is required for an object to be exported for RMI access?

    <p>It must implement the Remote interface (B)</p> Signup and view all the answers

    What role does the 'Shared proxy object' play in RMI?

    <p>It acts as a reference to remote objects (B)</p> Signup and view all the answers

    In the context of server callbacks in RMI, what is essential for the communication object?

    <p>It must extend the java.rmi.Remote interface (C)</p> Signup and view all the answers

    What must be enabled to activate client-side validations?

    <p>Client-side validation settings in web.xml (A)</p> Signup and view all the answers

    Which method is required to implement custom client-side validation?

    <p>validate() (A)</p> Signup and view all the answers

    Which annotation is used to specify the size constraints for a name property in a Bean?

    <p>@Size (A)</p> Signup and view all the answers

    In which situation are messages with FacesMessage.Severity typically used?

    <p>To indicate errors in forms (A)</p> Signup and view all the answers

    What feature does a Panel provide as a container for other widgets?

    <p>Dynamic event handling and user interaction (B)</p> Signup and view all the answers

    What functionalities does a Panel grid support?

    <p>Colspan and rowspan support (B)</p> Signup and view all the answers

    Which component is typically used to display error messages in the top right corner of the interface?

    <p>Growl (C)</p> Signup and view all the answers

    What is a characteristic of AJAX processing in forms?

    <p>It allows for partial processing and updates. (C)</p> Signup and view all the answers

    What is the purpose of the @Asynchronous annotation in the given MathSessionBean code?

    <p>It marks the method as capable of performing asynchronous operations, returning a <code>Future</code> object representing the eventual result. (A), It instructs the container to execute the method in a separate thread pool, improving performance by parallelizing operations. (B), It signifies that the method will be invoked asynchronously, allowing the caller to continue execution while the method completes. (C)</p> Signup and view all the answers

    What does the isDone() method in the code snippet Future r = mathBean.compute(20, 11); while (!r.isDone()) {...} Integer i = r.get(); check for?

    <p>If the asynchronous computation has completed successfully or encountered an error. (D)</p> Signup and view all the answers

    Which transaction attribute ensures that a new transaction is always created when a method annotated with it is invoked?

    <p>REQUIRES_NEW (B)</p> Signup and view all the answers

    What is the main difference between Container-managed and Bean-managed persistence in EJB?

    <p>Container-managed relies on JDBC calls, while Bean-managed allows for more flexibility using other data sources like LDAP. (A)</p> Signup and view all the answers

    Which of the following EJB components is NOT supported by EJB Lite?

    <p>Message-Driven Beans (C)</p> Signup and view all the answers

    Which of these features is NOT offered by an Embeddable Container for EJBs?

    <p>Enhanced scalability compared to traditional EJB deployments. (B)</p> Signup and view all the answers

    What is the purpose of the UserTransaction interface in the Bean-managed persistence model?

    <p>To initiate, commit, and rollback transactions manually within the EJB. (D)</p> Signup and view all the answers

    Which of the following scenarios is best suited for using an EJB Lite implementation?

    <p>A standalone batch processing application running within a single JVM. (A), A lightweight web application with a simple data model and minimal persistence requirements. (C)</p> Signup and view all the answers

    Study Notes

    Introduction

    • Lectures are 2 hours per week.
    • Midterm test - 10 points.
    • Team project (29 product, 5 documentation, 5 defense) - 39 points.
    • Final exam - 51 points (10 points for oral part).
    • Lower limits: Team project - 10 points, Final exam - 20 points.
    • Projects: Web (and mobile) application for 5 students.
    • Fewer students possible after consultation.

    Course Overview

    • Servlets, Java Server Pages
    • Maven, Testing and JAX (Java API for XML)
    • RMI (Remote Method Invocation) and JMS (Java Message Service)
    • EJB (Enterprise Java Beans) and Java Server Faces
    • PrimeFaces
    • Spring
    • Midterm test
    • Lectures by expert from practice
    • JPA (Java Persistence API), Hibernate
    • Google Web Toolkit
    • Android basics
    • Cloud
    • Advanced Android
    • Project defenses

    Java EE and Jakarta EE

    • 1998 - Sun started Java Professional Edition project.
    • 1999 - Java 2 Platform Enterprise Edition (J2EE) was born.
    • 2006 - J2EE was renamed to Java EE or Java Platform Enterprise Edition.
    • 2017 - Oracle decided to give away the rights for Java EE to the Eclipse Foundation (the Java language is still owned by Oracle).
    • 2018 - Community voted for the new name and picked Jakarta EE.

    Servlet Containers and Application Servers

    CGI Scripts

    • CGI stands for "Common Gateway Interface".
    • CGI script is an external program, called by the web server
    • Web server is the mediator between client and application.
    • It runs a new instance for each request (stateless).

    Servlets

    • A servlet is a small Java program.
    • It runs within a Web server (a Java class).
    • For a servlet not hosted in a distributed environment, the servlet container uses only one instance per servlet declaration.
    • For a servlet implementing the SingleThreadModel interface, the servlet container may instantiate multiple instances for a heavy request load and serialize requests to a particular instance.

    Servlets vs. CGI scripts

    • Advantages of servlets:
    • Running a servlet doesn't require creating a separate process each time.
    • A servlet stays in memory, so it doesn't need to be reloaded each time.
    • There's only one instance handling multiple requests, not a separate instance for every request.
    • It can keep context (session) in memory.
    • Untrusted servlets can be run in a "sandbox".
    • Disadvantage: More complicated configuration.

    Servlets

    • A servlet is any class that implements the javax.servlet.Servlet or jakarta.servlet.Servlet interface.
    • Most servlets extend javax.servlet.http.HttpServlet or jakarta.servlet.http.HttpServlet (to support HTTP protocol).
    • Others extend javax.servlet.GenericServlet or jakarta.servlet.GenericServlet (if not specifically HTTP).
    • Servlets have an init, service, and destroy method.

    Important Servlet Methods

    • When a servlet is first started, the init(ServletConfig config) method is called.
    • init should handle initializations.
    • Every servlet request results in a call to service(ServletRequest request, ServletResponse response).
    • service calls another method depending on the service type.
    • service handles multiple requests (must have thread safety).
    • When the servlet is shut down, the destroy() method is called.

    Servlet deployment

    • Web archive
    • Contains deployment descriptors (e.g., MANIFEST.MF).
    • Actual program code and libraries,
    • Configuration file(web.xml) defining mapping from URLs to servlet components in WEB-INF,
    • filters, init context, servlet mapping, errors handlers.
    • Configuration can be done using annotations.

    Methods and configuration

    • Init param (for given servlet)
    • Context param (for whole application)
    • Load on startup

    Configuration

    • Filters
    • Mostly predefined from libraries, Used for tasks like logging, security.
    • Servlet Mappings
    • Mapping URLs to servlet instances.

    HTTP requests

    • HTML form action attribute.
    • Almost always a GET or a POST request.
    • "get" - puts form data in the URL after "?".
    • "&" separates parameters.
    • "post" - enables sending large amounts of information.

    Servlet methods

    • Service method dispatches various HTTP method requests.
    • doGet used for GET requests.
    • doPost used for POST requests.

    A "Hello World" servlet

    • Example code for a simple "Hello World" servlet.

    The superclass

    • Every class must extend GenericServlet or a subclass of.
    • GenericServlet (protocol-independent),
    • Usually extend HttpServlet (for HTTP requests).

    The doGet method

    • This method serves a GET request.
    • Input in HttpServletRequest parameter.
    • Output via HttpServletResponse.
    • Uses request to get information sent.
    • Does not return a value, uses response for output.

    Input to the servlet

    • GET requests: parameters in URL(e.g.,name=value&name=value).
    • Spaces encoded as "+".
    • POST requests: parameters in request body (harder to see).
    • Parameter names can occur multiple times.

    Getting the parameters

    • Input parameters retrieved via HttpServletRequest object.
    • getParameterNames() returns an Enumeration of parameter names.
    • getParameter(name) returns the value of parameter name as a String.
    • getParameterValues(name) returns an array of values for parameter name.

    Example of input parameters

    • Example code snippet demonstrating how to retrieve input parameters from a request.

    Using the HttpServletResponse

    • The second parameter in doGet(and doPost).
    • Sets the MIME type of the reply to the client.
    • Uses PrintWriter to output character data.

    Using the PrintWriter

    • Method to produce the web page.
    • Creates the header string "\n".
    • Shows the use of ‘println’method to print html structure.

    Typical servlet operations

    • Input validation (can be done client-side).
    • Working with database (e.g., using API).
    • Uploading Files (using Commons IO and FileUpload library for example).

    Commons FileUpload

    • Depends on Commons IO.
    • FileItemFactory, ServletFileUpload, FileItem.
    • For storing files, a repository (typically/tmp) is needed.

    Direct handling (from servlet 3.0)

    • Request contains parts (e.g., Content-Type). • Methods such as getParts(). • More properties (e.g., getSize() getContentType())

    Annotations

    • Annotations enable a declarative style of programming
    • Annotations specify how to process declared elements
    • Three Retention Policies:
    • SOURCE (used by IDEs before compilation),
    • CLASS (processed during compilation and in class files),
    • RUNTIME (available in the runtime environment).

    Annotation declaration

    • Types of annotations:
    • normal (key-value pairs).
    • single-member (single value).
    • marker (no value).

    Normal Annotation

    • Example annotations with multiple parameters.

    Special annotations

    • Single-member annotations.

    Built-in Annotations

    • @Override - Indicates overriding a method from superclass.
    • @Deprecated - A program element marked as deprecated.
    • @SuppressWarnings - Suppresses specific compiler warnings.
    • Example usages for @Override, @Deprecated, @SuppressWarnings

    Meta-Annotations

    • @Target – Specifies the types of elements an annotation can be applied to.
    • @Retention – Specifies how long the annotation information will be retained
    • @Inherited – Indicates whether an annotation is inherited by subclasses
    • Example usages for @Target, @Retention, @Inherited

    Meta-Annotation Examples

    • Example usages of built-in meta-annotations.

    Meta-Annotation Inherited

    • How annotations of this type will be inherited.
    • Example code illustrating inheritance behavior

    Target values

    • Possible targets for the @Target metadata annotation
    • TYPE, TYPE_PARAMETER, FIELD, METHOD, PARAMETER, CONSTRUCTOR, LOCAL_VARIABLE, ANNOTATION_TYPE, PACKAGE

    References

    • Links to resources for servlets, configurations, and annotations.

    The problem with servlets

    • Servlets can be complex to manage & update.
    • It is harder to use web tools to create interfaces if HTML. is hard-coded into the servlet directly.

    JavaServer Pages

    • Alternate way to create servlets.
    • Written as standard HTML with embedded Java code.
    • JSP code is translated into Java servlets.

    JSP Processing

    • JSPs compiled on first request.
    • First page load may be slower.
    • HTML translated to println() within servlet instance.

    JSP Advantages

    • Ease of working with UI rather than pure Java classes.
    • Easier to add or modify UI components, as Java code is used within the HTML.

    JSP scripting elements

    • Three types of tags (depending on function):
    • <%=expression%> (for expressions).
    • <%code%> (for scriptlets).
    • <%!declaration%> (for declarations).

    Example JSP

    • Example of how to embed Java expressions into an HTML page using JSP.

    Implicit objects

    • Predefined variables (objects) available in JSPs: • request • response • out • config • page • exception • pageContext • session • application

    JSP scopes

    • Different scopes for JSP variables:
    • page
    • request
    • session
    • application

    Scriptlets

    • Insert Java code directly into a servlet method.
    • Not recommended to mix scriptlets with HTML structures.
    • It is important to not write too much logic into the scriptlets.

    Declarations

    • Declaring variables, methods to your servlet class using <%! %>tag.

    Directives

    • <%@page ...%> - Affects the servlet class itself.
    • <%@include ...%> - Inserts another file into the JSP page.
    • <%@taglib ...%> - Defines tags for reuse.

    The page directive

    • Defines attributes that apply to a page (attributes vary).
    • Attributes include: extends, import, session, buffer, autoFlush, info, errorPage, contentType,pageEncoding

    The include directive

    • Inserts a file into the current JSP page, treated another JSP.
    • URLs are usually relative to the current file, but if starts with "/" relative to the web server's home directory.

    JSP comments

    • Use special tags for comments that are not rendered in the client-side.

    JavaBeans

    • Reusable components for applications. • They encapsulate business logic. • Should have constructor, methods, Serializable, etc.

    Getter and setter

    • Methods for accessing and modifying bean properties (getters and setters).

    JavaBeans – Example

    • Sample JavaBean implementation (e.g., Frog).

    JavaBean properties

    • Bound properties for notification to other components about property change events. (PropertyChangeSupport) • Vetoable properties to get vetoing functionality from changes in properties (PropertyChangeSupport).

    Expression Language

    • Used for expression evaluation throughout JSPs and for dynamic interaction with business logic components.

    Expression language

    • EL allows page authors to use simple expressions to dynamically access data from JavaBeans components. • Tasks:

    • reading data from JavaBeans,
    • writing data to JavaBeans,
    • invoking methods on JavaBeans,
    • performing arithmetic operations, etc.

    Immediate and deferred evaluation syntax

    • Immediate evaluation tags: uses $ {}. • Deferred evaluation tags: uses # {}.

    Value Expressions

    • Rvalue: read-only data retrieval. • Lvalue: capable of modification. • Can access JavaBeans components, their properties, attributes, Java SE enumerated types, and implicit objects,

    Method Expressions

    • Invoking arbitrary public methods on beans. • Using: . and [ ] operators. • Parameterized method calls supported in the EL.

    JSP tags

    • Uses XML syntax.
    • Used to import tag libraries (e.g. JSTL - JSP Standard Tag Library).

    JSP predefined tags

    • Predefined tags for use in JSP are readily available, use without directives. • <jsp:include .../>- Inserts a specified file into JSP (Execution time). • <jsp:forward .../>- Redirects the user to another page (compute). • <jsp:getProperty .../>- Provides functionality to get specific properties of an object. • <jsp:setProperty .../> - Assign values to specific properties of an object. • The <jsp:useBean .../> tag is most common, used to create an instance of a JavaBean.

    JSP useBean tag

    • create or receive an instance of a JavaBean • Used for creating or instantiating a bean with a specific name and scope.

    References

    • Provide links for JSP

    Testing – basic concepts

    • Four levels of software testing (Unit, Integration, System, Acceptance, Regression).
    • Fixture – data for repeatable testing.
    • Test case – set of tests with a specific fixture for a single unit.
    • Test suite – a collection of test cases covering a system.

    Content

    • JUnit (a unit testing framework for Java)
    • Arquillian (a testing framework for integration testing)
    • Selenium (a framework for web browser automation)
    • Hudson / Jenkins (a framework for continuous integration)

    Testing in Java – JUnit

    • xUnit family standard
    • JUnit 4 does not use Java Annotations
    • Example function using JUnit assertions

    JUnit Fixtures, Exceptions, Timeout

    • @Before, @After - called before/after each test expected exceptions,
    • assertThrows
    • Timeout
    • examples

    JUnit Assertions

    • assertEquals, assertNull, assertNotNull, assertSame, assertFalse/assertTrue,.

    JUnit – Fail

    • Explicitly indicate test failure
    • Examples:fail(),fail(String message) • ExampleNumberGenerator

    JUnit Test Suite

    • Define test suites with suites of test cases to run.

    JUnit Test Runner

    • Example class for running the JUnit test suite.

    Integration Testing

    • Test multiple components together.
    • Arquillian for integration testing of REST APIs running in a container.
    • Use ShrinkWrap
    • Example calculator-junit_arquillian

    CDI (Contexts and Dependency Injection)

    • Contexts – lifecycle and interactions of stateful components.
    • Dependency Injection – injecting components. — The order of these is:
    • Container calls the bean constructor to construct the instance
    • Container initializes all the injected fields of the bean (in the same order)
    • All initializer methods are invoked
    • If any of these steps are missing or in wrong order, it is not portable and unexpected behavior may occur.

    Integration Testing

    • Test dependency injection, • CDI events, interceptors • @PostConstruct • @PreDestroy • Shrink Wrap example • CreateDeployment

    Functional Testing

    • Tests the functionality of the entire application, usually black-box testing. • Selenium for Web browser remote control • http://seleniumhq.org/

    Selenium

    • WebDriver – does not require selenium server • Remote Control – requires selenium server.

    Continuous Integration

    • Maintaining a code repository,
    • Automating the build,
    • Making the build self-testing,
    • Supporting team development,
    • Every commit should be built and tested,
    • Everyone can see test results,
    • Initial setup time required (Hudson and Jenkins).

    Jenkins

    • Easy installation, web GUI, settings build scripts, testing, reporting, Repository change support, RSS/Email/IM integration, JUnit/TestNG integration, distributed builds, plugin support.

    References

    • Provide links for JUnit, Arquillian, Selenium, and Hudson.
    • Provide links for build tools.

    Maven

    • Project management tool.
    • Dependency management.
    • Documentation.
    • Project lifecycle.
    • Convention over configuration
    • Common interface

    Maven project structure

    • Project root (foo folder),
    • Project object model (pom.xml),
    • Project sources(src/main/java/….)
    • Test sources(src/test/java/...),
    • Build output (target/....),
    • Common directory structure

    Maven project structure- web

    • Project root
    • Project object model
    • Project Java sources
    • Test sources
    • Build output
    • Output files(.war)

    Project Object Model

    • Basic information (groupID, ArtifactID, etc.)
    • Dependencies
    • Build
    • Reporting

    Lifecycles

    • Default lifecycle (e.g., build, testing, deployment).
    • Site lifecycle – creating documentations.
    • Clean lifecycle – removing generated stuff.

    Lifecycle phases

    • List of different phases of a lifecycle (e.g., validate, compile, package, verify, etc.).

    Other lifecycles

    • Site lifecycle, clean lifecycle

    Maven configuration

    • MAVEN_OPTS environment variable
    • settings.xml file (local repository, servers).
    • .mvn folder

    Plugins and goals

    • Plugin is a Java class with Maven specific metadata.
    • Goals can be called directly. • The phase of goals can be bound to a lifecycle phase. • Reports are used during site generation. • Examples for using Maven plugins and goals for compiling, testing, and packaging a project.

    Maven repository

    • Contains downloaded dependencies.
    • By default in ~/.m2
    • Can be changed by command line argument.

    Maven dependency resolution

    • Prioritization of dependencies resolution: (Local, Central, Remote).

    Maven dependency scopes

    • Scope types: compile, provided, runtime, test, system, import.

    Including custom library

    • When the required library is not in any repository.

    • maven install command (for local installation).

    Maven Archetypes

    • Project templates • Provide pre-configured project structures. • Examples of how to invoke mvn archetype:generate

    Creating maven project

    • Methods for creating a new Maven project from different applications.

    Maven plugins

    • Custom functionality
    • Calling other plugins.

    Content

    • JAX-RS • Java™ API for (XML) RESTful Web Services • JAX-WS • Java™ API for XML-Based Web Services

    JAX-RS introduction

    • State transfer
    • HTTP architecture.
    • typical client-server model: handled by different resources.

    REST (HTTP) methods

    • GET - retrieves a resource without side effects.
    • HEAD - similar to GET but does not return a body.
    • POST - creates or updates a resource.
    • PUT - creates or replaces a resource.
    • DELETE - removes a resource.

    JAX-RS and Jersey

    • Java defines REST via JSR 311 (JAX-RS).
    • Jersey is an reference implementation. • Server side: • Jersey servlet predefined classes • Registration in web.xml. • Base URL (e.g., http://hostname:port/context-root/url- pattern/path-of-rest-class). • Paths specified via annotations.

    Jersey DispatcherServlet

    • Jersey needs to be registered as the servlet dispatcher for REST services.

    • Where to look for server classes • Root path specification • Everything is configured in web.xml.

    web.xml example Jersey 2.x

    • Example of web.xml configuration for a Jersey 2.x REST application.

    web.xml example Jersey 1.x

    • Example of web.xml configuration for a Jersey 1.x REST application.

    JAX-RS annotations

    • @Path - sets the resource path.
    • @GET,@POST,@PUT,@DELETE - define HTTP methods.
    • @Produces - sets the response content types to MediaType.
    • @Consumes - sets the input content types.

    Jersey example

    • Example of a Jersey REST resource class and its usage in a GWT RPC workflow example.

    Form parameters

    • @FormParam annotation. • Needs a Form submit needed
    • Consumes APPLICATION_FORM_URLENCODED.

    Matrix parameters

    • GET parameters separated using ';' delimiter • Call example: • /mapping;year=1234;country=CZ;author=Me.

    Path parameters

    • Parameters separated by '/'. • Call example: • /mapping/2001/11/12

    File upload

    • Jersey Multipart, • InputStream with file data, • FormDataContentDisposition.

    File download

    • Bean must return streamed content. • Example code snippet for downloading a file.

    JAXB

    • Java™ Architecture for XML Binding(JAXB)

    JAXB example

    • Example code snippet using JAXB.

    References

    • Provide links for JAXB, JAX-RS and Jersey.

    JAX-WS Introduction

    • Java API for XML-based Web Services (JAX-WS)
    • JSR 224.
    • Extends JAX-RPC 1.0.
    • What are Web Services
    • Message or RPC oriented approach
    • SOAP
    • SOAP messages are sent via HTTP
    • Typically used for XML-based communication.

    SOAP

    • XML-based protocol • Envelope structure • Encoding rules • conventions for representing web service invocations and responses • Web methods (GET, POST, PUT, DELETE) • Server-side Java interface • defining methods. • Client-side proxy for invocation.

    SOAP Message

    • XML containing elements: • Envelope,Header,Body,Fault.

    JAX-WS architecture

    • Implementations (e.g., Apache AXIS, Glassfish Metro).
    • Illustrative diagram showing the interaction between the client side and server side objects.

    JAX-WS Web Integration

    • Glassfish Metro
    • Endpoint specified in sun-jaxws.xml
    • Web.xml
    • WSServletContextListner
    • WSServlet
    • @WebService
    • @WebMethod

    sun-jaxws.xml

    • Example sun-jaxws.xml configuration.

    web.xml

    • Example implementation of a web.xml configuration file.

    JAX-WS

    • Endpoints
    • RPC (Remote Procedure Call) style web service endpoint
    • Document style web service endpoint.

    JAX-WS RPC style

    • Synchronous style
    • Easy to implement
    • Poor performance
    • @WebService • @SOAPBinding(style=Style.RPC) • Accessibility on URL (named by package) • QName defines target service endpoint • Communication via service port.

    JAX-WS RPC example

    • Example of a JAX-WS RPC style web service.

    JAX-WS RPC Example (2)

    • Using wsimport tool to generate client code that will access the deployed web service.

    JAX-WS Document style

    • Asynchronous style • Greater overhead • Better for custom data types. • @WebService @SOAPBinding(style = Style.DOCUMENT, use = Use.LITERAL) • SOAP messages will include complete data type info (as opposed to just method invocation)

    JAX-WS Document example

    • Example of JAX-WS Document style web service.

    JAX-WS Document example (2)

    • More information on how wsgen CLI tool can be used for creating artifacts from wsdl.

    JAX-WS Document example (3)

    • Example of JAX-WS Document style web service client.

    JAX-WS MTOM

    • Message Transmission Optimization Mechanism supports sending binary attachments.

    Web Service handlers

    • Client handlers - intercept client calls, handle authentication, etc.
    • Server interceptors - validate requests, authorize clients, etc.

    Client handler

    • Create the client for the web service. • Create SOAP Handler • Handler Configuration • Handler Mapping • SOAPHandler interface: implements SOAPHandler<SOAPMessageContext>.

    Client handler (2)

    • Intercept mapping specified in XML file. • @HandlerChain, • Examples for handler chaining and mapping.

    Server handler

    • Create Web Service • Create SOAP Handler, • Handler Configuration, • Handler Mapping, • SOAPHandler interface: handleMessage().

    Server handler (2)

    • Intercept mappings are defined in XML file.

    References

    • Provide links for JAX-WS.

    Content

    • RMI (Remote Method Invocation) • JMS (Java Message Service)

    RMI

    • Remote method invocation
    • Distributed Java
    • TCP/IP transport layer
    • Client/server architecture • RMI layers: Stub, Skeleton.
    • RMI uses proxy design pattern. • A naming or directory service is usually run on a well-known host and port number (often port 1099).

    RMI protocols

    • RMI uses JRMP and IIOP protocols for interoperability. • JRMP is proprietary • IIOP is CORBA’s protocol using TCP/IP as the transport.

    RMI architecture

    • The interaction between clients and servers.

    RMI features

    • Simplifies communication with remote application
    • Supports local method calls (on both client & server).
    • Supports security (authentication/authorization). • Layer design (stub and skeleton).

    RMI principles

    • Java RMI framework usage. • naming registry (rminame registry - provides information on the location of the remote object)
    • Naming or directory service,
    • RMI includes RMI registry.

    RMI Registry

    • The RMI registry is a naming and directory service. • enabling remote clients to find remote object references.

    RMI Naming

    • Naming static class (Bind, list, lookup, rebind, unbind).

    Server implementation (RMI)

    • Shared proxy object • Shared proxy must be implemented. • Registry is created. -- If not already running • Service is bind to the name -- the name is used by clients for lookup

    Client implementation (RMI)

    Basic client usage for RMI calls

    Server callback

    Asynchronous calls, different port, UnicastRemoteObject. • exportObject

    RMI security

    • Initialize security manager
    • Secuirity manager restricts code from network connections • Package javax.security.manager

    References

    • Provide links for RMI.

    JMS

    • Asynchronous message exchange • JMS implementations are called JMS providers. • Different providers are not interoperable.
    • Reliable delivery.
    • Different Providers (e.g., OpenMQ, JBossMQ, WebSphere MQ, ActiveMQ, RabbitMQ, ZeroMQ).

    Messaging domains

    • P2P (Point to Point) -- Only one consumer. • Each queue can have more senders.
    • Pub/Sub -- Multiple providers and consumers.

    JMS architecture

    • JMS interface specification
    • JMS Provider implementations
    • JNDI
    • Connection factories
    • Destinations

    JMS programing model

    • Connection factory • TopicFactory,QueueFactory • Destination − Topic − Queue • Session • Consumer, Producer

    JMS messages

    • Map Message,
    • Text Message,
    • Object Message,
    • Stream Message,
    • Byte Message,

    JNDI

    • Java Naming and Directory Interface
    • JMS is tightly coupled to JNDI.
    • Provider - queuing services lookup.
    • Contains a context.

    JNDI association, context, system, namespace

    • JNDI objects for binding names,
    • Locating objects.

    JNDI architecture

    • Provides an abstraction to various directory services

    • Common API for client access, • JNDI SPI - service provider interface, • Custom naming service using JNDI SPI • Naming service may be LDAP, DNS, NIS, NDS, RMI, CORBA.

    JNDI services

    – Access directory services. • Common API for client access. • Directories are structured trees of information

    Message consumptions

    • Asynchronous approach • A client register a message listener.
    • Synchronous approach • Subscriber or receiver explicitly calls receive method.

    JMS features (additional)

    • Additional features (message acknowledgement, priorities, persitent delivery mode, control of message expiration, durable subscriptions, message transactions)

    Message acknowledgements

    • Auto, explicit, and lazy client acknowledgements. • Handling possible message duplication.

    Persistent delivery mode

    • Default mode (logged to persistent store) • Non-persistent delivery mode (not stored to a persistent store)

    Priorities, expirations

    • 10 levels (0-lowest, 4-default, 9-highest) • Queues and topics can be large • Expiration time (TTL) and priorities

    Durable subscriptions and transactions

    • Durable subscriptions survive application restarts. • Transactions group operations as atomic units (rollback).

    Transactions

    • Grouping of operations into an atomic unit of work. • Rollback - undo and destroy messages • Commit – all messages are sent and consumed messages acknowledged

    ActiveMQ

    • How to run the broker (e.g. from https://..).
    • Default URL of the broker (usually an Application Server defined constants. )

    References

    • Provide necessary resources to handle JMS.

    Contents of EJB

    • Enterprise bean class • Business interfaces • Other classes • Deployment descriptor (optional)

    EJB

    • Enterprise JavaBeans (EJB) • Execute within an EJB container. • Server side components, • Part of application server.

    EJB server

    • Part of an application server hosting EJB containers.

    • Several common application servers
    • GlassFish(Oracle), WebSphere(IBM), WebLogic(Oracle), WildFly(Red Hat),WebObjects(Apple), ... • EJB specification outlines EJB server functionalities (naming, transactions, security, persistence, concurrency, lifecycle, messaging, timers, etc.).
    • EJB don't interact directly with the EJB server.

    EJB Container

    • Runtime environment for EJB components.
    • Transparent to the client. • Services (transaction, concurrency, pooling, security).

    Multitiered Java EE Applications

    • Client tier • Web tier • Business tier • EIS tier.

    EJB Components

    • EJB components are modular, reusable server-side components,

    Enterprise Java Bean types

    • Session beans (Stateless, Statefull, Singleton).
    • Message-driven beans • Entity beans - persistent data storage.

    Accessing Session Beans

    • Clients access session beans via dependency injection (@EJB) or JNDI lookup.

    Dependency Injection Example

    • Using dependency injection with EJB.

    JNDI names

    • Naming service, JNDI names used to access beans (examples for accessing using different JNDI types).

    Calendar-based Timer Service

    • Annotation @Schedule.
    • Sample usage (dayOfWeek, hour, minute, second, timezone).

    Asynchronous Invocation

    • Methods can be invoked asynchronously. • Return values are often Future<V>
    • Example for handling asynchronous calls.

    EJB Transactions

    • Container-managed (default)

    • TransactionAttributeType (REQUIRED,REQUIRES_NEW, MANDATORY etc.). • Bean-managed transactions Using a javax.transaction.UserTransaction interface.

    EJB Lite

    • Subset of EJB full
    • no remote interfaces, no message-driven beans, no JMS, no web services, etc.

    Embeddable Container

    • Running client and EJB in the same JVM. • Support for testing.

    Contents of EJB

    • Enterprise bean class, business interfaces, other classes, and deployment descriptor.

    Deployment Descriptors

    • XML file containing deployment settings including transactional settings.

    References

    • Provide detailed links for JSF, Java Persistence, and EJB.

    Introduction

    • GWT is a framework for building AJAX applications using Java.
    • GWT compiles Java code to JavaScript.

    GWT Application Structure

    • Directory structure in a typical GWT application. • Distinguish between a client side and server side components (e.g., the RPC servlet interface definition).

    GWT Application Structure – Maven

    • Directory structure for a Maven-based GWT project. • Distinguish between a client-side and server-side components (e.g., application module definitions).

    Maven Plugin for GWT Application Structure

    • Directory structure.

    Application structure (GWT)

    • Separating client-side and server-side components (with different code execution environments- host page).

    HTML Host Page

    • File structure • Use of JavaScript code files (hello.nocache.js, etc.) • Slots for elements to be rendered.

    Hello World Entry Point (GWT)

    • Main function for the entry point of the GWT app.

    Modules

    • Similar to packages,
    • Bundles of GWT libraries/codes,
    • Used to manage code dependencies.

    Hello World Module

    • The simplest hello world definition in a GWT module.

    GWT standard modules

    • Core GWT code, HTTP library, JSON library, GWT testing framework, XML creation and parsing - logical names and content.

    Deployment

    • Creating a WAR file, • Deploying WAR to a server, • Running the application.

    Deployment in NetBeans

    • How to deploy a GWT application in a platform like NetBeans.

    Development mode

    • How to start and run a GWT application in development mode.

    Super development mode

    • How to run Super development mode.

    • Use of a dedicated server/port.

    Problems

    • Common issues when running a GWT application,

    • port occupancies and bootstrap file caching, etc

    Production mode

    • Details of how GWT generates client-side JavaScript for the deployment mode • How to ensure that client applications can cache the compiled codes.

    User Interface

    • Basic GWT UI components, such as,
    • Labels, Buttons, TextBoxes,
    • Using client-side CSS styling
    • Well-defined class hierarchy.

    CSS Styling

    • How to style elements using CSS- similar to standard web development

    Basic widgets

    • Typical GWT widget classes that are used in different contexts.

    UI objects

    • HTML
    • Image
    • Anchor

    Form Widgets

    • Label, Button, PushButton, ToggleButton, CheckBox, RadioButton, ListBox, TextBox, PasswordTextBox, TextArea, RichTextArea, FileUpload, Hidden.

    Complex Widgets

    • Tree, MenuBar, DatePicker, CellTree, CellList, CellTable, CellBrowser

    • MenuBar example

    Layout Panels

    • Layout panel definitions and attributes

    Event handling

    • Event handling functionality includes typical listening for events, such as click.

    Custom Widgets

    • Create custom components. • Extend classes similar to typical Java or extend Composite.

    GWT UI Binder

    • Framework for separating functionality and view of UI.
    • Using XML for UI definitions and bindings.

    Steps for using UI binder

    • Creating UI declaration,
    • Creating Java counterpart,
    • Binding Java UI fields and elements in code
    • Attaching CSS.

    JSF Managed Beans

    • Using Managed Beans to organize data and manage the application. • Accessing session beans

    Dependency Injection

    • Example on how to use dependency injection using a container like Spring

    No-interface view

    • EJB 3.1 version. • No need to use interfaces anymore

    Message Driven EJB

    • Message driven bean usage • Messaging model (point-to-point, pub-sub).

    Types of EJB

    • Session beans • Stateless • Statefull • Singleton • Message-driven beans • Entity beans

    Configuring datasource

    • How to configure a database connection in Spring.

    Executing SQL queries

    • Methods to execute SQL queries.

    Spring Transaction Management

    • Local transactions. • Global transactions • Declarative/Programmatic transactions

    Spring Web MVC framework

    • Model, View, and Controller pattern.

    Dispatcher servlet

    • Handles HTTP requests.
    • Consults HandlerMapper to determine which controller to use
    • DispatcherServlet does all the job. • The controller decides which method to call to get the data from the database if necessary.

    Configuration

    • Declaring servlets in web.xml,
    • Specifying URL pattern,
    • Defining controller and mappings.

    Defining controller

    • @Controller
    • @RequestMapping.

    Creating JSP views

    • Creating JSP files for Views

    Spring Security

    • Managing user roles • Login (default or custom appearance)

    Spring security configuration (XML based)

    • Configuration structure for Spring security using XML (e.g. form login)

    XML configuration from

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