Top 40 SOAP Interview Questions and Answers

SOAP Interview Questions and AnswersSOAP (Simple Object Access Protocol) is a technical specification that helps Web services interact with other systems over the Internet. Its main goal is to make communication between different platforms and operating systems smooth and seamless.

Alongside REST, SOAP has become popular among developers working on projects that involve integrating systems. That’s why it’s valuable for both freshers and experienced professionals in this field to learn about SOAP API.
To help you quickly understand SOAP, especially for technical interviews, we’ve put together a list of commonly asked SOAP web services interview questions and answers. We suggest you spend some time reviewing these questions to excel in SOAP interviews.

Answer:

SOAP or Simple Object Access Protocol means a communication protocol that facilitates data exchange across different networks. It is based on XML & enables communication over different applications of Linux, Windows through the internet. SOAP defines HTTP messaging protocols & XML. It also uses a range of other protocols like POP3, FTP, SMTP, etc. SOAP provides data transportation between web services & is used for broadcasting the message. It is a way to structure data before transmitting it.

Answer:

SOAP provides a user interface accessible to a client object, the request it sends goes to a server, accessed through a server object. UI creates some methods & files consisting of a server object and the interface’s name to the server object. It uses HTTP to send an XML to the server by using the POST method, which analyzes the method & sends the result to a client. The server creates more XML containing responses to the user’s interface request using HTTP. The client can deploy any approach to send XML, such as POP3 protocol or SMTP server, to pass the messages or reply to queries.

Answer:

SOAP API is used to update, create, delete or retrieve records, like leads, accounts, & user-defined objects. You can use SOAP API to perform searches, manage passwords with more than 20 different calls using the SOAP API in any programming language that supports web services.

Answer:

  • PutAddress():It is used to enter the address in a webpage & an address instance on the SOAP call.
  • PutListing():It is used to enable a complete XML document insertion into the web page. It receives an XML file as an argument & transports an XML file to XML parser liaison, which reads & inserts it into a SOAP call as a parameter.
  • GetAddress():It is used to obtain a query name & result that best matches the query. The name is sent to SOAP call in the form of a text character string.
  • GetAllListing():It is used to return full list in the XML format.
  • Native Method Stack:It consists of all the native methods used in applications.

Answer:

One of the critical hindrances or obstacles observed by SOAP users is the Firewall security mechanism. In this case, all HTTP ports except those that bypass the firewall are locked, like HTTP port 80 & HTTP port. In some cases, there occurs the technical issue of mixing the specification of the message transport with the message structure is observed.

Answer:

There are two different approaches for developing SOAP-based web services, which are as follows:

  • Contract-first approach: The contract is defined by WSDL & XML & then Java classes are derived from a contract.
  • Contract-last approach: Java classes are defined, then the contract is generated, which is usually a WSDL file from the Java class.

The “Contract-first” method is the most preferred approach for developing SOAP-based web services.

Answer:

SOAP is like another XML document that has the following elements:

  • Envelope: It is defined as the compulsory root element which translates the XML document & determines the end & starts a SOAP message.
  • Header: It has optional header attributes of a message containing a specific information on an application. It can occur multiple times intended to add new functionalities as well as features.
  • Body: It is a mandatory element containing the call & response messages. It is also defined as a child element of an envelope with all application-derived XML data exchanged as part of a SOAP message.
  • Fault element: A fault element handle errors occurring during the processing of the messages. If the error is present, then that element appears as the child element of the body. However, there can only be a fault block.

Answer:

Below are the fundamental syntax rules for a SOAP message:

  • Must use an encoded XML;
  • Must use envelope namespace;
  • Must use encoding namespace;
  • Must not contain a DTD reference;
  • Must not have an XML processing instruction

Answer:

SOAP uses the application layer & transport layer; HTTP & SMTP are the valid protocol for an application layer. Amongst the two, HTTP is preferable. HTTP GET method is deployed to send SOAP requests & specifications containing details of the HTTP POST methods.

Answer:

Below are the key characteristics of the SOAP element:

  • SOAP message possesses a root envelope element
  • An envelope is a mandatory part of a SOAP message
  • If the Envelope contains a header element, it must not have more than one. Also, it must appear as the first child of the Envelope
  • When a SOAP version changes, the envelop version also changes simultaneously
  • SOAP envelope is specified by the prefix ENV & an Envelope element
  • The optional SOAP encoding is specified by using a namespace & optional encoding style element.

Answer:

The SOAP protocol class provides simple access methods for all the apps on the internet. It offers the following functionalities:

  • Call:The class provides the main functionality for remote methods for which a call is needed. It helps create the call() & specify the encoding style of a registry assigned if necessary. The call() function is used by the RPC call, which represents the options of the call object.
  • Deployment Descriptor:A class is used to provide information about the SOAP services. It enables easy deployment without needing other approaches.
  • DOM2 Writer: It is a class that uses & serializes DOM node as XML string to provide more functionalities.
  • RPC Message:A class used as a base class that replies & calls to the request submitted to a server.
  • Service Manager: It is a class that provides lists then outputs all SOAP services.

Answer:

These are functionalities provided for a web page by the SOAP protocol:

  • HTTPUtils: It renders the POST method functionality through which a request can be reached in a secured manner.
  • Parameter: It denotes an argument to an RPC call used by both the client & the server.
  • Response: It refers to an object representing an RPC response by both server & client, but the result comes only after the method invocation.
  • TCPTunnel: It is an object that provides a property of listening on a given port & forwards all the host and port names.
  • TypeConverter: It is a functionality to convert an object of one type to another. It is invoked with a class in the form object.

Answer:

Advantage of SOAP are as follows:

  • It is a platform as well as language-independent.
  • SOAP de-couples encoding & communications protocol from a runtime environment.
  • Web service can receive or acquire a SOAP payload from the remote service.
  • Anything can generate XML, from C++ code to Perl scripts to J2EE app servers.
  • It uses XML to receive & send messages.
  • It uses standard internet HTTP protocol
  • SOAP runs over HTTP & removes firewall problems.  When using protocol HTTP, an RPC call maps to an HTTP request automatically & thereby; an RPC response maps to an HTTP response.
  • In contrast to DCOM, RMI, CORBA SOAP is very simple & easy to use.
  • It acts as a protocol for transferring information in a distributed & decentralized environment.
  • SOAP is transport protocol independent & can be accessed in coordination with other protocols.
  • It is also vendor-neutral.

Answer:

Some disadvantages of SOAP are:

  • It is much slower than other middleware technologies.
  • As we use HTTP in SOAP for transporting messages & not for defining ESB or WS-Addressing the interaction of parties over, a message is fixed.
  • Application protocol level is problematic since HTTP usability for different purposes is not present.

Answer:

  1. SOAP REST
    SOAP is a protocol designed with a specification. It includes a WSDL file containing the required information on what the web service does apart from web service location. REST refers to an architectural style wherein the web service can be treated as a RESTful service only if it follows the constraints of being a:

    • Stateless
    • Client-Server
    • Uniform Interface
    • Cacheable
    • Layered System
    SOAP cannot utilize REST as SOAP is a protocol, while REST is an architectural pattern. REST can use a SOAP as the underlying protocol for the web services since it is just an architectural pattern.
    SOAP only permits an XML format. REST permits different data formats.
    SOAP-based reads cannot be cached. REST reads can be easily cached.
    SOAP is similar to a custom desktop application closely connected to a server. REST is like a browser that uses standard methods. An application has to fit inside it.
    SOAP is slower than the REST. REST is faster than a SOAP.
    It runs on the HTTP but envelopes a message. It deploys the HTTP headers to hold metadata or information.

Answer:

  • Top-down SOAP web services first include creating the WSDL document to build a contract between the client & the web service and then writing the required code. It is also called the contract-first approach. The top-down approach is difficult to implement as classes need to be written to confirm a contract established in the WSDL. An advantage of using the Top-Down approach is that it enables both client & server code to be parallelly written.
  • Bottom-up SOAP web services first require the code to be written & then the WSDL document is created. It is also termed the contract-last approach. As the WSDL is generated based on a code, the bottom-up approach is relatively easier to implement. Client codes need to wait for the WSDL from the server-side to start working.

Answer:

SOAP web services are commonly created through JAX-WS API. However, several other frameworks in Java are available to implement SOAP web services, such as Jersey, Apache Axis, CodeIgniter, Apache CXF, etc. These frameworks are different from JAX-WS API & work on a Servlet model to highlight the business logic as the SOAP web services.

Answer:

  • RPC Style
    • In RPC style, WSDL documents are generated on the basis of method name & its parameters. In the WSDL document, no type definitions are present. Under the RPC style, WSDL is hard to validate against the schema. RPC style message is tightly coupled.
  • Document style
    • web services can be easily validated against the predefined schema & content type. In Document style, parameters are sent in an XML format & the message is loosely coupled.

Answer:

The following are some fundamental features of SOAP:

  • SOAP is a communication protocol that was designed to communicate between applications via the internet.
  • It is a format for sending messages.
  • It is platform-independent.
  • SOAP is also language-independent.
  • SOAP is extensible, easy & simple.
  • SOAP enables you to get around firewalls.
  • It was developed as a W3C standard.

Answer:

A SOAP message refers to an XML document containing these elements:

  • An Envelope element: It identifies an XML document as a SOAP message.
  • A Header element: containing the header information.
  • A Body element: containing response & call information.
  • A Fault element: containing status & errors information.