Question:

What is Novell exteNd Web Services SDK?

Answer:

Novell exteNd Web Services SDK is a runtime and compiler for executing and developing Web Service client and server applications. Novell exteNd WSSDK is a 100% pure Java implementation, which supports Web Services standards such as SOAP and WSDL. It brings the familar programming model of Java RMI to the Web Services world.

The Novell exteNd WSSDK compilers provide support for both application programmers who are developing client programs that need to access existing Web Services and for application programmers who are developing server programs that implement those Web Services. The runtime provides stubs and skeletons as an abstraction for the underlying XML protocols.

Question:

Why do I need Novell exteNd Web Services SDK?

Answer:

Novell exteNd Web Services SDK provides a programming model on top of SOAP. Clients can invoke Web Services as remote Java objects rather than using low-level SOAP API's. On the server side Web Services are simply implementations of Java interfaces.

Question:

Where can I use Novell exteNd Web Services SDK?

Answer:

Novell exteNd Web Services SDK is primarily used for the following two things:

• To invoke existing Web Services from Java. With Novell exteNd WSSDK you can develop Java programs that interact with SOAP 1.1 Web Services running on the Web using the familiar RMI programming model.
• To develop new SOAP 1.1 Web Services and expose them on the Web. The Novell exteNd WSSDK programming model for server implementations requires you to just implement the business methods of an application. The server is deployed in a standard J2EE servlet container.

Since Novell exteNd WSSDK supports both client and server side development, it can of course be used to build complete end-to-end distributed applications that exchange messages via the SOAP protocol. Note that server side Web Services can delegate to existing back-end systems, including CORBA servers, EJB components, JMS destinations, etc.

Question:

What gets installed on my system?

Answer:

The Novell exteNd Web Services SDK installation consist of the Novell exteNd WSSDK binaries, libraries, documentation and sample programs. These files are put in the directory you specified during installation.

Question:

How do I un-install Novell exteNd Web Services SDK from my system?

Answer:

First, ensure that the directory where you installed Novell exteNd Web Services SDK is in your CLASSPATH. The un-install with the following command:

 java -jar _uninst/uninstall.jar

This will take you through the un-install process and remove the Novell exteNd WSSDK files from your system.

Question:

Where do the Web Services run?

Answer:

The Web Services can run in any server that supports the J2EE servlet API. Novell exteNd Web Services SDK also supports a simple stand-alone Web Server for deploying Web Services.

Question:

Why a servlet? Can't I just deploy a Java class?

Answer:

Servlet provides a proven and stardard deployment environment.

Question:

What does the wsdl2java compiler do?

Answer:

The wsdl2java compiler translates a WSDL document into Java RMI. The portType with it's operations and messages gets mapped into a Java Remote Interface with methods corresponding to the WSDL definition. After generating a Java interface, the wsdl2java compiler invokes the rmi2soap compiler to create SOAP stubs and skeletons. Please consult the tutorial for a detailed description of wsdl2java.

Question:

When I run wsdl2java on a WSDL document I get the following warning: type <some type> not declared in namespace <some namespace>, using Object instead.

Answer:

This happens when the WSDL document references a type, which has not been declared. As an example, this happens if a type is not qualified with a prefix and not declared in the current xmlns. In most cases you need to add a xmlns: <some namespace> declaration to the document and add a prefix to the type such as 'xsd:string'.

Question:

What does the xsd2java compiler do?

Answer:

The xsd2java compiler compiles XML Schema types into JavaBeans. As an example, an XML Schema complexType gets mapped into a JavaBean where the complex type's attributes and elements are bean properties. Please consult the tutorial for a detailed description of xsd2java.

Question:

What does the rmi2soap compiler do?

Answer:

The rmi2soap compiler translates Java RMI into SOAP stubs and skeletons. A stub allows client programs to access Web Services in a easy-to-understand and type-safe manner without having to worry about the underlying wire protocol. In a similar manner, a skeletons allow Web Services to be implemented in an easy and type-safe manner. Please consult the tutorial for a detailed description of rmi2soap.

Question:

What does the rmi2wsdl compiler do?

Answer:

The rmi2wsdl compiler translates Java RMI into a WSDL document. The Java interface with its methods, parameters, return values and exceptions gets converted into a WSDL document with corresponding portType, operations, input, output and fault messages. The rmi2wsdl compiler further generates a SOAP binding and service for the portType. Please consult the tutorial for a detailed description of rmi2wsdl.

Question:

I ran rmi2wsdl but the generated WSDL document has no SOAP binding?

Answer:

You need to run it with the -soap flag. Please consult the man page for a full description of the command line parameters.

Question:

What does the jwebserv tool do?

Answer:

The jwebserv tool is a very light-weight Web Server that speaks HTTP 1.0. It allows developers to deploy standard WAR files that contain a Novell exteNd WSSDK Service implementation. The Novell exteNd WSSDK Server also allows developers to deploy and un-deploy services using a browser interface. Please consult the tutorial for a detailed description of jwebserv.

Question:

What does the tcptunnel tool do?

Answer:

The tcptunnel tool intercepts TCP connections and displays what is exchanged between a client and a server. It acts as a visual "pipe" between a port on the local host and a port on a remote host.

Question:

What does the java2rmi tool do?

Answer:

The java2rmi wizard is a graphical tool for converting regular Java classes into remote interfaces (RMI). You can select classes from a pull down list and sebsequently select methods from the class to make available in the generated RMI.

Question:

When I run a client, I get the following exception: Exception in thread "main" com.sssw.jbroker.web.ServiceException: bad content type = text/html

Answer:

One of the following problems are likely:

• The URL does not point to a Web Service. The content type for Web Service URL's is always text/xml.
• A Web Service is not currently deployed at the specified URL. This causes the Web Server to return an html document with an error message.

Question:

When I run a client, I get the following exception: Exception in thread "main" javax.naming.NamingException: unable to load <some class>

Answer:

This is most likely a CLASSPATH problem. Ensure that the class from the error message is available to the jvm (e.g. try to type 'javap <some class>). If <some class> refers to a generated class, this can also happen if you are trying to run a client before running the wsdl2java or rmi2soap compiler.

Question:

When I run a client, I get the following exception: com.sssw.jbroker.web.ServiceException: unable to find "jBroker" transport handler for <some protocol>

Answer:

This happens if you use a protocol, which is not recognized by Novell exteNd WSSDK. In the current version, Novell exteNd WSSDK only recognizes the http, https, and jms protocols.

Question:

When I run a client, I get the following exception: Exception in thread "main" java.rmi.ConnectException: Connection refused

Answer:

This is most likely because the HTTP port you are using is not accepting requests. Make sure that there is an HTTP server running on the port you're trying to reach. As an example, if your client program is trying to invoke a Web Service on http://localhost:8080, there has to be an HTTP server running on port 8080 on you local machine.

Question:

When I run a client, I get the following runtime exception: Exception in thread "main" com.sssw.jbroker.web.mapping.MarshalerNotFoundException: no serializer found for <some class>

Answer:

You need to register a marshaller for the class. This is typically done using the follow code:

 DefaultTypeMappingRegistry registry = new DefaultTypeMappingRegistry();
 mapper.importMappings("my.private.type.mappings");
 ((Stub)stub)._setTypeMappingRegistry(registry);

Where the 'stub' object is what you previously looked up in JNDI.

Question:

How do I run the Novell exteNd Web Services SDK tools with more memory?

Answer:

You can pass flags to the jvm using the -J command line flag. To set the maximum heap size to 250 MB you can for instance run the wsdl2java compiler like this:

   wsdl2java -J-Xmx250m myfile.wsdl

Question:

When I start 'jwebserv' I get the following error message: 'failed to start web services server: "java.net.BindException: Address already in use"'

Answer:

This means that another program is already running on that port. You must either stop the currently running program or start the Web Server on a different port.

Question:

When I run a WSSDK client, I get the following exception: Exception in thread "main" java.lang.NoClassDefFoundError: com/sssw/shr/util/AgCipherSuitesSingleton.

Answer:

You need to add CSHelper.jar to your CLASSPATH.

Question:

What is a type mapping?

Answer:

A type mapping defines how to map between Java objects and XML. The mapping contains a Java class, a serializer and de-serializer class, the namespace of the XML type, the local name of the XML type, and finally the location of the XML schema for the XML type.

Question:

What is a serializer?

Answer:

A serializer converts a Java object into XML by writing the state of the Java object to an output stream. A serializer must implement the Serializer interface.

Question:

What is a de-serializer?

Answer:

A de-serializer converts a XML back into a Java object by reading the state of the Java object from an input stream. A de-serializer must implement the Deserializer interface.

Question:

What is a marshaler?

Answer:

A marshaler is a base interface for a serializer and de-serializer. A marshaler must implement the Marshaler interface.

Question:

Why do I need marshalers?

Answer:

Although Novell exteNd Web Services SDK supports schema compilation and automatically generates Java types for many XML Schema types, the xsd2java compiler does not support the entire XML Scheme. You may need to write a marshaler for a type not supported by the schema compiler, or if you need special, custom serialization.

Question:

What do the BeanMarshaler and PublicFieldMarshaler do?

Answer:

Novell exteNd Web Services SDK supports two general purpose marshalers that can be used in most situations. The BeanMarshaler treats the marshaled object as a JavaBean and reads or writes XML based on the bean properties. The PublicFieldMarshaler does the same but using public fields rather than JavaBean properties. You may also use the ValueTypeMarshaler, which serializes both bean properties and public fields.

Question:

Can I replace the Novell exteNd WSSDK type mapping for java.util.Map?

Answer:

No, it is not possible to replace the built-in type mappings. But you can create your own subclass of Map, and then register a marshaler for that type.

Question:

How does wsdl2java deal with in/out parameters?

Answer:

The wsdl2java compiler generates holders, which encapsulate the value. For in/out parameters, you can set the holder's value prior to invoking the operation. For in/out and out parameters, you can read the value set by the server once the invocation has completed.

Question:

Does the wsdl2java and rmi2wsdl compilers support overloaded method names?

Answer:

Yes, both WSDL and RMI support overloaded method names. In WSDL, you must name the input and output elements of the operation definition to support this.

Question:

Why does rmi2wsdl set 'use=literal' in the generated WSDL document when the Jave type is org.w3c.dom.Element?

Answer:

Because the is no 'element' type in XML Schema. Also, if your Java type is Element, the most appropriate way to map it to WSDL is by setting the message to be encoded in the SOAP binding.

Question:

Why can't I mix Element and regular Java types in a method signature?

Answer:

In WSDL, the parameters in a Java method correspond to parts in a message. In the SOAP encoding, you can only set an entire message as literal or encoded, so there is no WSDL equivalent of mixed literal and encoded messages.

Question:

What is JAX-RPC?

Answer:

JAX-RPC is the Java API for XML-Based RPC, i.e. Java API's for writing client/server applications that communicate using XML messages. Novell exteNd WSSDK is an implementation of the JAX-RPC standard.

Question:

What is SAAJ?

Answer:

The SOAP with Attachments API for Java (SAAJ) provides a DOM style interface for dealing with SOAP messages. The tree-like structure of the SAAJ API is similar to W3C's DOM API's and the SAAJ 1.2 interfaces in fact extend the W3C DOM interfaces. The SAAJ API is based on the SOAP specification and the SOAP Messages with Attachments specification. For more information about SAAJ, click here.

Question:

What is WS-I?

Answer:

The Web Services Interoperability (WS-I) Organization is an open, industry organization chartered to promote Web services interoperability across platforms, operating systems, and programming languages. Novell exteNd WSSDK supports the WS-I Basic Profile 1.0.

Question:

What is SOAP?

Answer:

SOAP means Simple Object Access Protocol and is a general protocol for invoking on services. Although SOAP is not tied to HTTP, it is commonly used to access Web Services that are running on the Internet via SOAP messages packaged into HTTP POST requests. The SOAP 1.1 specification is a W3C note, which can be downloaded from here.

Question:

Is SOAP the same as CORBA?

Answer:

CORBA is a complete programming environment for distributed and heterogeneous object systems, which includes an object model, wire protocol (IIOP), client and server programming language API's, and several standard system services, such as naming, security and transactions. SOAP is roughly equivalent to IIOP in CORBA.

Question:

What does a SOAP message look like?

Answer:

A SOAP message is an XML document where the root element is an envelope. The envelope contains a header and a body. The header can optionally carry information, depending on the client/server contract. The body contains the SOAP request or response, e.g. the parameters to invoke an RPC or the return values.

Question:

Is SOAP tied to any programming language or platform?

Answer:

No, SOAP is just a wire protocol that can be supported by any programming language and platform that supports HTTP. By using HTTP as the underlying transport and XML to describe the data, SOAP is a fairly ubiquitous protocol for tying together heterogeneous applications running on the Web.

Question:

Does SOAP define a security model?

Answer:

No, the current version of SOAP relies on HTTP for security. The SOAP messages are exchanged as HTTP POST's with an XML message in the payload of the HTTP request. SOAP can also run over HTTPS and the handler (Web Service) for the SOAP message can provide basic authentication. Although not standardized, a SOAP message could contain headers with security attributes.

Question:

What is WSDL?

Answer:

WSDL means Web Service Description Language and is an XML format for describing services as a sequence of port types, which each have a set of operations with input, output and fault messages. WSDL also supports defining bindings to popular Internet protocols such as SOAP, MIME and HTTP. The WSDL 1.1 specification is a W3C note, which can be downloaded from here.

Question:

What is XMLP?

Answer:

XMLP (XML Protocol) is W3C activity with the objective to define a XML-based protocol for distributed systems. XMLP was recently renamed to SOAP 1.2. You can look here for more information.

Question:

Are there any other FAQ's on SOAP, WSDL or XML available?

Answer:

Yes, you can try one of these:

• SOAP Frequently Asked Questions
• jGuru's Extensible Markup Language (XML) FAQ
• The XML FAQ
• SOAP Web Services FAQ