DEVELOPING WEB SERVICES WITH JAVA

1. DEVELOPING WEB SERVICES WITH JAVA WSDL & SERVICE REGISTRY

2. CONTENTS • Elements of WSDL • Web Service Registry • Steps to configure the registry Server and use the JAXR to publish, query and delete registry on registry services. • Exercises

3. Platform A Service 1 …………. …………. …………. Platform B Service 2 …………. …………. …………. SERVICE DESCRIPTION LANGUAGE – SDL Description of service written in SDL Specifies functionality of service Lists the parameters required by the exposed method Compatibility Issues Lists parameters returned by methods Documents the Web service contract (messages that the Web Service will generate and accept)

4. Web Service ……… ……… ……… WEB SERVICE DESCRIPTION LANGUAGE – WSDL or WISDEL • XML file describing Web services acts as a contract between the Web service consumer and the Web service • Location of Web Service • Type of protocol to be used • Allow specifying the way in which a service can be access • Use to explain how a particular Web Service works. It provides businesses with a standardized way of describing how applications and processes can interact online. • A WS proxy supports communication Web Service Consumer

5. WSDL FOR SERVICE PROVIDERS & CONSUMERS

6. WSDL DOCUMENT STRUCTURE • WSDL being an XML document begins with an XML declaration that specifies the XML version as 1.0 and the character encoding as UTF-8. • Consists of six elements • definitions • types • message • portType • binding • service Abstract Definitions Concrete Definitions Platform and Language Independent Machine or Language Specific bindings Port Types services messages types modifies ports operations

7. WSDL DOCUMENT STRUCTURE (cont) <wsdl:definitions targetNamespace="http://localhost:8081/axis/Calculator. • definitions • Is the root component of the WSDL file • ThetargetNamespaceattribute declares a namespace to which all names declared in an element will belong • The purpose of namespaces is to avoid naming conflicts • Acts as a container for the elements types, message, portType, binding and service. • Defines the name of the Web Service and also one or more namespaces used by its child elements.

8. WSDL DOCUMENT STRUCTURE (cont) <wsdl:types> - <schema targetNamespace="urn:fibonacci" xmlns="http://www.w3.org/2001/XMLSchema">   <import namespace="http://schemas.xmlsoap.org/soap/encoding/" /> - <complexType name="ArrayOf_xsd_int"> - <complexContent> - <restriction base="soapenc:Array">   <attribute ref="soapenc:arrayType" wsdl:arrayType="xsd:int[]" />   </restriction>   </complexContent>   </complexType>   </schema>   </wsdl:types> • types • Defines the data type of the information exchanged between applications. • Is mandatory only if the data type is other than the built-in data types of XML Schema. Example of XML schema’s built-in types are string, integer and so on

9. WSDL DOCUMENT STRUCTURE (cont) • message • Describes the content of messages exchanged by applications. • Specifies the service’s request and response mechanism • Not dependent upon any protocol i.e. there is no naming convention for message names. Ex: add Request, add Response • Divided into parts (arguments in method) • Each part is defined by the <part> element • A part may be visualized as a parameter value, or the return value in a typical RPC • A message element may contain zero or more <part> elements <wsdl:message name="calFibonacciRequest"> <wsdl:part name="in0" type="xsd:int"/> </wsdl:message>

10. WSDL DOCUMENT STRUCTURE (cont) • portType • Defines operations provided by the Web Service. It often bean references to the message elements • The operations (methods) are collectively referred to as portType. They are defined on every portType • Operations (input output messages) are to be defined by specifying the <operation> element • operations • Distinguishes between the input, output, or fault message • Operations are apart from the message definitions <wsdl:portType name="Fibonacci"> <wsdl:operation name="calFibonacci" parameterOrder="in0"> <wsdl:input message="impl:calFibonacciRequest" name="calFibonacciRequest"/> <wsdl:output message="impl:calFibonacciResponse" name="calFibonacciResponse"/> </wsdl:operation> … </wsdl:portType>

11. WSDL DOCUMENT STRUCTURE (cont) • binding • Describes how the input and output messages of each operation defined in portType element will be transmitted over the Internet from one application to another • Represents the concrete descriptions of the operations • Specifies the representation of parameters for a Web method • Are specified for each method of service consumption • The encoding of the input and output messages for WS is defined in the binding section <wsdl:binding name="fibonacciSoapBinding" type="impl:Fibonacci"> <wsdlsoap:binding style="rpc" transport="http://schemas.xmlsoap.org/soap/http"/> <wsdl:operation name="calFibonacci"> <wsdlsoap:operation soapAction=""/> <wsdl:input name="calFibonacciRequest"> <wsdlsoap:body encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" namespace="urn:fibonacci" use="encoded"/> </wsdl:input> <wsdl:output name="calFibonacciResponse"> <wsdlsoap:body encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" namespace="urn:fibonacci" use="encoded"/> </wsdl:output> </wsdl:operation> … </wsdl:binding>

12. WSDL DOCUMENT STRUCTURE (cont) • service • Specifies methods offered by the Web service • Services are available on ports, which have specific addresses • Specify the binding, port name, and the port addresses (endpoint) for each access method • port • Endpoint describe network address which is consumed by WS consumer • Support a communication between WS (application) and client • Reuse (The port is dynamically) <wsdl:service name="FibonacciService"> <wsdl:port binding="impl:fibonacciSoapBinding" name="fibonacci"> <wsdlsoap:address location="http://localhost:8081/axis/fibonacci"/> </wsdl:port> </wsdl:service>

13. UDDI • Is a platform-independent, XML-based registry for businesses worldwide to list themselves on the Internet. • Provides standard mechanisms for businesses to describe and publish their Web Services, discover published Web Services and use them. • Contains references to specifications called as Technical Models, or tModels, which describe the working of Web Services. The tModel is built upon a programming model and schema that are platform and language independent. • There are several steps for using the registry • The software companies populate the registry by describing various tModels and specifications common to a business. • UDDI programmatically assigns a Unique Universal Identifier (UUID) to each tModel and business applications query the registry to discover services of other companies and integrate this data easily with each other over the web. • Finally, this becomes a dynamic process where search and discovery is performed automatically based on the available services.

14. White Pages Yellow Pages Green Pages tModel bS bS bS bT bT tModel tModel UDDI DATA STRUCTURE • Provides five core data structures that are used to represent an organization, its services, implementation technologies, and relationships with the other businesses publisherAssertion (pA) bindingTemplate (bT) businessEntity (bE) businessService (bS) bE bE pA pA bS bS bS bT bT tModel tModel

15. UDDI PUBLISHER API • Allows to add, modify, and delete service-related data from the registry • allows organizations to save their own businessEntity, businessService, bindingTemplate, tModel, and publisherAssertion data structures in a UDDI registry, and to remove them when necessary

16. UDDI INQUIRY API • Is used to search and read data from a UDDI registry. • Is used to query the UDDI registry and fetch specific UDDI data structures

17. ebXML

18. ebXML ARCHITECTURE

19. Is a superset of UDDI The ebXML registry stores information about the service provider and the Web Service The ebXML repository also stores the business process documents of the service provider Internally, the registry is connected to the repository. The repository stores different objects such as Core Components, Bus Process Information Meta Models, Business Documents, Collaboration Protocols Profiles and Collaboration Protocols Agreement The clients communicate with the registry using the following two interfaces Object Manager Provides the methods to create new objects within the registry and affect state transitions on existing objects. Includes different methods namely approveObjects(), deprecateObjects(), removeObjects(), submitObjects(), addSlots() and removeSlots(). Object Query Manager Provides the methods to find and access the objects created within the registry. Includes different methods namely getClassficationTree(),getClassfieldObjects(), getContent() submitAdhocQuery() and getRootClassficationnodes() REGISTRY & REPOSITORY

20. Defines a standard language to configure business systems for business collaboration execution between collaborating parties or business partners Is a set of individual messages exchanged among business partners. Depicts who the trading partners are, their roles, the documents exchanged and its structure. In other words, a Business Process defines the Business Collaboration. The main parts of Business Collaboration: Business Collaboration Specification: is a set of roles interacting through a set of specialized protocol by exchanging Business Documents between business partners. Business Transaction: is an atomic unit of work in a trading arrangement between two business partners. A Business Transaction is conducted between two parties playing opposite roles in the transaction. The roles are always in the form of request and response. Business Document Flows: in Business Transaction, by default, each requesting role has one Business Document. The responding role may not have a Business Document. The Business Documents are composed from registry-usable Business Information Objects. The ebXML reuses the Business Information Objects from a Core Component Library to create the Business Documents. Choreography: is used to define which Business Transaction follows which Business Transaction. The realization of the choreography is done by the transition between two Business Transactions. A Binary Collaboration has several transitions and a transition has a “from” Business State and a “to” Business State. Patterns: are a set of defined transaction interactions. The use of predefined patterns combines the flexibility of specifying an infinitive number of specific transactions and collaborations with a consistency. This facilitates faster design, faster implementation, and enables generic processing. BUSINESS PROCESSES

21. The CPP is an XML document that contains information about a business and the way exchanges information with other businesses. The CPA is an intersection of two CPP documents. The CPA is derived from two or more CPPs. ebXML Collaboration Protocol Profiles and Collaboration Protocol Agreements

22. Also called Aggregated Component. A Core Component is a reusable building block that contains information about a business concept. For example, for a concept such as purchase order, the core components are date of purchase order, sales tax and total amount. The ebXML Messaging Service (ebXML MS) provides the message wx functionality within the ebXML infrastructure. ebXML MS is an entity used by the Business Service Interface software to send and receive XML messages from one point to another. ebXML MS is based on TCP/IP, FTP, HTTP and SMTP protocols. EBXML MS uses packages data in SOAP messages and transmits them using HTTP, TCP/IP, FTP or SMTP protocol. ebXML CORE COMPONENTS & MESSAGING SERVICE

23. Tool requirement: Tomcat 5.0 for jwsdp (java web service developer pack) jwsdp 1.5 jdk 1.4 Netbeans IDE 5.5.1 Step 1: Setting up above the requirement tools Alternative, unzip the package all in one including Tomcat 5.0, jwsdp 1.5 and jdk 1.4 Step 2: Adding the new server for Netbeans 5.5.1 Step 3: Starting to test the server SETTING UP & CONFIGURING REGISTRY SERVER

24. Step 1: Unziped the package (Drive C is recommended) SETTING UP & CONFIGURING REGISTRY SERVER

25. Step 2: Adding the new server for Netbeans 5.5.1 In tab Runtime, right click on the Server, click Add Server SETTING UP & CONFIGURING REGISTRY SERVER Choose the Tomcat 5.0 Type the Server Name Click Next Button

26. Step 2: Adding the new server for Netbeans 5.5.1 (cont) SETTING UP & CONFIGURING REGISTRY SERVER Browse to the Tomcat 5.0 directory Typing the username and password that can be found at the tomcat-user.xml in the conf directory Click finish Button

27. Step 2: Adding the new server for Netbeans 5.5.1 (cont) SETTING UP & CONFIGURING REGISTRY SERVER

28. Step 3: Starting to test the server Right click the name of server that is setting up, click Start SETTING UP & CONFIGURING REGISTRY SERVER

29. Step 1: Creating Application to using registry with JAXR Step 2: Create Connection Factory Step 3: Setting the Connection attributes Step 4: Create Connection from Connection Factory Step 5: Create the RegistryService from Connection Step 6: Get the LifeCycleManager or QueryManager from RegistryService Step 7: Configuring the Connection Authentication with username password default (testuser – testuser) Step 8: Determine the action (publish, query, or delete) on the registry using JAXR API Requirement packages javax.xml.registry.*; javax.xml.registry.infomodel.*; javax.xml.registry.infomodel.RegistryObject; with jar files soap.jar, jaxr-api.jar,jaxr-impl.jar jaxb-api.jar, jaxb-impl.jar, jaxb-libs.jar, jaxb.xjc.jar STEPS TO USE REGISTRY WITH JAXR

30. CONNECT TO REGISTRY SERVER • Create Connection Factory ConnectionFactory factory=ConnectionFactory.newInstance(); • Create Connection from Connection Factory • Using URL and registry server attributes that are accessed. Ex: connProps.setProperty("javax.xml.registry.queryManagerURL", “http://localhost:8080/RegistryServer/”); connProps.setProperty("javax.xml.registry.lifeCycleManagerURL", “http://localhost:8080/RegistryServer/”); connProps.setProperty("javax.xml.registry.factoryClass", "com.sun.xml.registry.uddi.ConnectionFactoryImpl"); • Create connection. Ex: factory.setProperties(connProps); Connection conn=factory.createConnection(); • Notes: In flexibility, the URLsshould be puton the properties file. Ex: the publish.properties file that is put in root application query.url=http://localhost:8080/RegistryServer/ publish.url=http://localhost:8080/RegistryServer/ user.name=testuser user.password=testuser

31. GET REGISTRY SERVICE • Get Registry Service Object RegistryService rs=conn.getRegistryService(); • Get Query và LifeCycle Manager BusinessQueryManager bqm=rs.getBusinessQueryManager(); BusinessLifeCycleManager blm=rs.getBusinessLifeCycleManager(); • Configuring the Authentication for Connection (that is applied with publish and delete action) PasswordAuthentication passwdAuth=new PasswordAuthentication(username, password.toCharArray()); Set creds=new HashSet(); creds.add(passwdAuth); conn.setCredentials(creds);

32. PUBLISH REGISTRY • Create object • Creating object using the BusinessLifeCycleManager with the createXXX methods • Organization, createOrganization(Name) & setDescription: define Name & Description for organization • Service, createService(String) và setDescription: define the branch or services that are provided by the organization • PersonName & createPersonName: define Contact • The contact objectincludes TelephoneNumber, PostalAddress, EmailAddress • Classification: taxonomy following the ClassificationSchema(ordering) & Key (id) • Other information as ExternalIdentifier & createExternalIdentifier • Save/ Store the Object into Registry • Using the saveOrganizations(Collection) method. Ex BulkResponse br=blm.saveOrganizations(orgs); if(br.getStatus()==JAXRResponse.STATUS_SUCCESS)

33. EXAMPLE • Register the organization to Registry Service with the following information as: • Name: ABCL New Corp (Brand of a Celebrity) • Services: Selling a celebrity brand (Services of a celebrity brand) • Contact: Michelle Pfeifer • Tel: 199-600-5403 • Address: 14739 Highway Park Apartments New Jersey NY USA 09140 • Email: big@abcl.com • Classification: ntis-gov:naics • Key:uuid:C0B9FE13-179F-413D-8A5B-5004DB8E5BB2 • ...

34. EXAMPLE (cont) • publish.properties query.url=http://localhost:8080/RegistryServer/ publish.url=http://localhost:8080/RegistryServer/ user.name=testuser user.password=testuser #if you are behind a firewall this needs to be configured http.proxy.host= http.proxy.port=

35. EXAMPLE (cont) • Publish.java public class Publishing { String username="testuser"; String password="testuser"; String regUrli=""; String regUrlp=""; Properties connProps=new Properties(); private static final String USER_NAME="user.name"; private static final String USER_PASSWORD="user.password"; private static final String PROXY_HOST="http.proxy.host"; private static final String PROXY_PORT="http.proxy.port"; public void assignUserProperties(Properties props){ String queryURL=((String)props.get("query.url")).trim(); String publishURL=((String)props.get("publish.url")).trim(); String user=((String)props.get(USER_NAME)).trim(); String pw=((String)props.get(USER_PASSWORD)).trim(); if(queryURL!=null)regUrli=queryURL; if(publishURL!=null) regUrlp=publishURL; if(user!=null) username=user; if(pw!=null) password=pw;} public void setConnectionProperties(){ connProps.setProperty("javax.xml.registry.queryManagerURL", regUrli); connProps.setProperty("javax.xml.registry.lifeCycleManagerURL", regUrlp); connProps.setProperty("javax.xml.registry.factoryClass", "com.sun.xml.registry.uddi.ConnectionFactoryImpl"); }

36. EXAMPLE (cont) • Publish.java public void executeTest(Properties properties)throws JAXRException{ try{ assignUserProperties(properties); setConnectionProperties(); ConnectionFactory factory=ConnectionFactory.newInstance(); factory.setProperties(connProps); Connection conn=factory.createConnection(); RegistryService rs=conn.getRegistryService(); BusinessQueryManager bqm=rs.getBusinessQueryManager(); BusinessLifeCycleManager blm=rs.getBusinessLifeCycleManager(); PasswordAuthentication passwdAuth=new PasswordAuthentication(username, password.toCharArray()); Set creds=new HashSet(); creds.add(passwdAuth); conn.setCredentials(creds); Collection orgs=new ArrayList(); Organization org=blm.createOrganization(blm.createInternationalString("ABCL New Corp")); org.setDescription(blm.createInternationalString("Brand of a Celebrity")); Service service=blm.createService(blm.createInternationalString("Selling a celebrity brand")); service.setDescription(blm.createInternationalString("Services of a celebrity brand")); User user=blm.createUser(); PersonName personName=blm.createPersonName("Michelle Pfeifer"); org.setPrimaryContact(user); TelephoneNumber telephoneNumber=blm.createTelephoneNumber(); telephoneNumber.setNumber("199-600-5403"); telephoneNumber.setType(null); PostalAddress address=blm.createPostalAddress("14739", "Highway Park Apartments", "New Jersey", "NJ", "USA", "09140", ""); Collection postalAddress=new ArrayList(); postalAddress.add(address); Collection emailAddresses=new ArrayList(); EmailAddress emailAddress=blm.createEmailAddress("big@abcl.com"); emailAddresses.add(emailAddress);

37. EXAMPLE (cont) • Publish.java Collection numbers=new ArrayList(); numbers.add(telephoneNumber); user.setPersonName(personName); user.setPostalAddresses(postalAddress); user.setEmailAddresses(emailAddresses); user.setTelephoneNumbers(numbers); ClassificationScheme cScheme=blm.createClassificationScheme(blm.createInternationalString("ntis-gov:naics"), blm.createInternationalString("")); Key cKey=(Key)blm.createKey("uuid:C0B9FE13-179F-413D-8A5B-5004DB8E5BB2"); cScheme.setKey(cKey); Classification classification=(Classification)blm.createClassification(cScheme, "System Related Services", "15000"); org.addClassification(classification); ClassificationScheme cScheme1=blm.createClassificationScheme(blm.createInternationalString("D-U-N-S"), blm.createInternationalString("")); Key cKey1=(Key)blm.createKey("uuid:8609C81E-EE1F-4D5A-B202-3EB13AD01823"); cScheme1.setKey(cKey1); ExternalIdentifier ei=blm.createExternalIdentifier(cScheme1, "D-U-N-S number", "08-146-6849"); org.addExternalIdentifier(ei); org.addService(service); orgs.add(org); BulkResponse br=blm.saveOrganizations(orgs); if(br.getStatus()==JAXRResponse.STATUS_SUCCESS){ System.out.println ("Published and saved the organization details");} else{ System.err.println("One or more JAXRExceptions occured during the save operation: "); Collection exceptions=br.getExceptions(); Iterator iter=exceptions.iterator(); while(iter.hasNext()){ Exception e=(Exception)iter.next(); System.err.println(e.toString());}}} catch(JAXRException e){e.printStackTrace();} }

38. EXAMPLE (cont) • Publish.java public static void main (String[] args) { try{ System.out.println ("main start"); Publishing bqt=new Publishing(); Properties properties=new Properties(); properties.load(new FileInputStream("publish.properties")); System.out.println ("have file"); bqt.executeTest(properties); System.out.println ("Finish"); }catch (JAXRException e){ System.out.println ("Failed " + e.getMessage()); }catch(IOException e){System.out.println ("Unable toopen properties file"); } } }

39. QUERY • Some attributes: Collection findQualifiers, Collection namePattern, Collection classifications, Collection specifications, Collection externalIdentifiers, Collection externalLinks • Query by Name: • Assign to findQualifiers to define the finding and sorting way (Ex: FindQualifier.SORT_BY_NAME_ASC or FindQualifier.CASE_SENSITIVE_MATCH) • namePattern: finding with % character • Get return values BulkResponse br=bqm.findOrganizations(findQualifiers, namePatterns, null, null, null, null); if(br.getStatus()==JAXRResponse.STATUS_SUCCESS)

40. EXAMPLE • Setting the JAXR Client to get Registry Services, get BusinessLifeCycleManager Collection findQualifiers=new ArrayList(); findQualifiers.add(FindQualifier.CASE_SENSITIVE_MATCH); findQualifiers.add(FindQualifier.SORT_BY_NAME_ASC); Collection namePatterns=new ArrayList(); namePatterns.add("%"+sName+"%"); BulkResponse br=bqm.findOrganizations(findQualifiers, namePatterns, null, null, null, null); if(br.getStatus()==JAXRResponse.STATUS_SUCCESS){ Collection org=br.getCollection(); Iterator iter=org.iterator(); while(iter.hasNext()){ Organization o=(Organization)iter.next(); //tham số truyền RegistryObject System.out.println ("Name: " + getName(o)); System.out.println ("Description: " + getDescription(o)); System.out.println ("Key: " + getKey(o));}} else{ System.out.println ("Not found");}

41. EXAMPLE(cont) public static void main (String[] args) { String sname="ABCL New Corp"; System.out.println ("main start"); try{ queryByName qBN=new queryByName(); Properties properties=new Properties(); properties.load(new FileInputStream("publish.properties")); System.out.println ("have file"); qBN.jaxrQueryByName(properties, sname); System.out.println ("finish"); }catch (JAXRException e){ System.out.println ("Failed " + e.getMessage()); }catch(IOException e){ System.out.println ("Unable toopen properties file");}}

42. QUERY (cont) • Query by Classification: • Define Classification schema ClassificationScheme cScheme=bqm.findClassificationSchemeByName(null, "ntis-gov:naics"); • Define classification content thatis found Classification classification=blm.createClassification(cScheme, "System Related Services", "15000"); Collection classifications=new ArrayList(); classifications.add(classification); • Get return value BulkResponse br=bqm.findOrganizations(null, null, classifications, null, null, null); if(br.getStatus()==JAXRResponse.STATUS_SUCCESS) • Query by argument service: studying in jwsdp document on Sun

43. EXAMPLE • Setting JAXR Client to get Registry Services, get BusinessLifeCycleManager ClassificationScheme cScheme=bqm.findClassificationSchemeByName(null, "ntis-gov:naics"); Classification classification=blm.createClassification(cScheme, "System Related Services", "15000"); Collection classifications=new ArrayList(); classifications.add(classification); BulkResponse br=bqm.findOrganizations(null, null, classifications, null, null, null); if(br.getStatus()==JAXRResponse.STATUS_SUCCESS){ Collection org=br.getCollection(); Iterator iter=org.iterator(); while(iter.hasNext()){ Organization o=(Organization)iter.next(); //tham số truyền RegistryObject System.out.println ("Name: " + getName(o)); System.out.println ("Description: " + getDescription(o)); System.out.println ("Key: " + getKey(o));}} else{ System.out.println ("Not found");}

44. EXAMPLE (cont) public static void main (String[] args) { String sname="ntis-gov:naics"; System.out.println ("main start"); try{ queryByClassification qBN=new queryByClassification(); Properties properties=new Properties(); properties.load(new FileInputStream("publish.properties")); System.out.println ("have file"); qBN.jaxrQueryByClassification (properties, sname); System.out.println ("finish"); }catch (JAXRException e){ System.out.println ("Failed " + e.getMessage()); }catch(IOException e){ System.out.println ("Unable toopen properties file");}}

45. REMOVE REGISTRY • Using deleteObject(Collection) method of (Business)LifeCycleManager object with id registry. • The authentication is requirement

46. EXAMPLE • Configuring JAXR Client to get Registry Services, get BusinessLifeCycleManager andauthentication Key orgKey=blm.createKey(key); Collection keys=new ArrayList(); keys.add(orgKey); BulkResponse br=blm.deleteOrganizations(keys); if(br.getStatus()==JAXRResponse.STATUS_SUCCESS){ Collection org=br.getCollection(); Iterator iter=org.iterator(); while(iter.hasNext()){ Organization o=(Organization)iter.next(); System.out.println ("Name: " + getName(o)); System.out.println ("Description: " + getDescription(o)); System.out.println ("Key: " + getKey(o));}} else{ System.out.println ("Not found");}

47. EXAMPLE (cont) public static void main (String[] args) { String skey="121b5064-5b71-21b5-3f48-9eb3dfd16b24"; System.out.println ("main start"); try{ Deleting dr=new Deleting(); Properties properties=new Properties(); properties.load(new FileInputStream("publish.properties")); System.out.println ("have file"); dr.jaxrDelete(properties, skey); System.out.println ("Finish"); }catch (JAXRException e){ System.out.println ("Failed " + e.getMessage()); }catch(IOException e){ System.out.println ("Unable toopen properties file");} }

48. Do it yourself all the demo again EXERCISES