Mulesoft Developer Interview Questions

1. What is Mulesoft used for?
Answer: Mulesoft is an integration platform that allows developers to connect applications together quickly and easily, enabling them to exchange data.

2. Explain the difference between Callout and Service Invoke?

Callout: We can call the service using callout or with service invoke. Use the Callout if we need to mediate a message (without calling an intermediate service) and then call a service provider.

The Callout provides the simplest model for this configuration.

Service Invoke: You need to interact with multiple services, and produce an output that combines service responses. The Service Invoke primitive does not switch from request flow to response flow.

Use the Service invoke if we need to call an (Mulesoft Training )intermediate service.

Example: We can use an intermediate service to adjust a message or to validate a message externally. The mediation flow contains Service Invoke mediation primitive, and a Callout node that is connected to the service provider there will be no intermediate service.

3. What are Shared Resources in Mule and how are they been used?
Answer: We can make connectors as a reusable component by defining them as common resources and expose them to all applications deployed under the same domain, these resources are known as shared resources. These shared resource needs to be defined inside Mule Domain Project and then referred to each of the projects that are meant to use the elements in it.

4. What are the advantages of Soap Web Services?

WS Security: SOAP defines its own security known as WS Security.

Language and Platform independent: SOAP web services can be written in any programming language and executed in any platform.

Disadvantages of Soap Web Services:

Slow: SOAP uses XML format that must be parsed to be read. It defines many standards that must be followed while developing SOAP applications. So it is slow and consumes more bandwidth and resources. (E learning portal)

WSDL dependent: SOAP uses WSDL and doesn’t have any other mechanism to discover the service.

5. What Is Connector In Mule?
Answer: A connector is in charge of controlling the usage of a particular protocol. It is configured with parameters that are specific to this protocol and holds any state that can be shared with the underlying entities in charge of the actual communications.

For example, a JMS connector is configured with a Connection, which is shared by the different entities in charge of the actual communication.

6. How Message In Mule Is Composed?
Answer: A Mule message is composed of different parts: The payload, which is the main data content carried by the message.

The properties, which contain the meta information much like the header of a SOAP envelope or the properties of a JMS message. Optionally, multiple named attachments, to support the notion of multipart messages.

Optionally, an exception payload, which holds any error that occurred during the processing of the event

7. What Is Transport Service Descriptor In Mule?
Answer: The connector has a technical configuration known as the Transport Service Descriptor (TSD). This hidden configuration is automatically used for each instance of the connector. It defines technical parameters such as what classes to use for the message receivers, requesters, and dispatchers; or the default transformers to use in inbound, outbound, and response routers. Knowing these default values is essential to grasping the behavior of transport.

8. What is Shared Context?
Answer: Shared Context: Context is a temporary area that is created along with Service Message Object (SMO) in the Mediation Flows. Shared Context is a type of context which is present in the SMO. Shared Context is mainly used when we are using the Aggregation process where we need to Iterate the BO for Certain times. Shared Context maintains Aggregation data between Aggregation (FanOut and FanIn) primitives. The Content (data) which is present in the shared context BO does not persist across Request and Response flows i.e The Data in the Shared Context which is used in Request flow can not be used again in Response flow.

9. What Is Payload In Mule?
Answer: The content of a message, also known as the payload. It is wrapped in an instance of org. mule. api. Mule Message, which provides different means of accessing the payload under different forms. A Mule Message also contains properties, much like the header of a SOAP envelope or the properties of a JMS message, and can also have multiple named attachments.

10. What are the main Features of Mule ESB? What are the different ESBs in the market?

1)The main Features of Mule ESB are:

  • It is very simple and easy to use-Drag and drops Graphical design
  • SLA monitoring and API management
  • High scalability
  • We can deploy in a One-click cloud or on-premise deployments

2)Different ESB’s in Market are:

  • Talend
  • Mule ESB
  • JBoss Fuse ESB

11. What is a SOAP Web Service?
Answer: SOAP stands for Simple Object Access Protocol. It is an XML-based protocol for accessing web services. SOAP is a W3C recommendation for communication between two applications.

SOAP is XML based protocol. It is platform independent and language independent. By using SOAP, you will be able to interact with other programming language applications.

12. What Difficulties Mule Does Encompass?
Transport: applications can accept input from a variety of means, from the file system to the network.

Data format: speaking the right protocol is only part of the solution, as applications can use almost any form of representation for the data they exchange.

Invocation styles: synchronous, asynchronous, or batch call semantics entail very different integration strategies.

Life cycles: applications of different origins that serve varied purposes tend to have disparate development, maintenance, and operational life cycles.

13. What Is Transport Layer In Mule??
The transport layer is in charge of receiving or sending messages. This is why it is involved with both inbound and outbound communications. A transport manifests itself in the configuration by the following elements: connectors, endpoints, and transformers.

A transport also defines one message adapter. A message adapter is responsible for extracting all the information available in a particular request (data, meta information, attachments, and so on) and storing them in transport-agnostic fashion in a Mule message.

14. What Is Component In Mule?
Answer: Components are the centerpiece of Mule’s services. Each service is organized with a component at its core and inbound and outbound routers around it. Components are used to implement a specific behavior in service. This behavior can be as simple as logging messages or can go as far as invoking other services. Components can also have no behavior at all; in that case, they are pass-through and make the service act as a bridge between its inbound and outbound routers.

15. When Does Mule Instantiate A Connector?
If Mule figures out that one of our endpoints needs a particular connector, it will automatically instantiate one for us, using all the default values for its different configuration parameters. This is a perfectly viable approach if we are satisfied with the behavior of the connector when it uses its default configuration. This is often the case for the VM or HTTP transports. Note that Mule will name these default connectors with monikers such as a connector. http. 0.

16. Explain ESB Integration core principles?
Transformation: Data transformation between canonical data formats and specific data formats required by each ESB connector.

Transportation: Transport protocol negotiation between multiple formats. Such as HTTP, JMS, JDBC.

Mediation: Providing multiple interfaces for a) supporting multiple versions of a service for backward compatibility or b) to allow for multiple channels to the same underlying component implementation. This second requirement may involve providing multiple interfaces to the same component, one legacy interface (flat file) and one standard compliant (SOAP/XML) interface.

Non-functional consistency: For a typical ESB initiative, this can include consistency around the way security and monitoring policies are applied and implemented.

17. What Is Endpoint In Mule?
Answer: An endpoint represents the specific usage of a protocol, whether it is for listening/polling, reading from, or writing to a particular target destination. Hence it controls what underlying entities will be used with the connector they depend on. The target destination itself is defined as a URI. Depending on the connector, the URI will bear a different meaning; for example, it can represent a URL or a JMS destination.

18. What is the MuleSoft Anypoint platform used for?
Answer: MuleSoft’s Any point Platform of integration products is designed to tie together software as a service (SaaS) and on-premises software.

19. What is the functionality of Fan-in and Fan-out?
Fan-out: We can use the Fan Out primitive to fire the output terminal once (with the input message) or fire the output terminal multiple times. You can use Fan Out in isolation or as part of a Fan Out and Fan In combination.

Fan-In: Fan In is always partnered with a Fan Out in the same flow and acts as a decision point for when to continue flow execution. It receives a number of messages until a decision point is reached, at which point the last message to be received is propagated to the output terminal. The Fan In primitive may only be used in combination with Fan Out.

20. What Are Differences Between Mule And Other Commercial Esbs?
Answer: The prescriptive deployment model, whereas Mule supports a wide variety of deployment strategies. Prescriptive SOA methodology, whereas Mule can embrace the architectural style and SOA practices in place where it is deployed. Mainly focused on higher-level concerns, whereas Mule deals extensively with all the details of integration. Strict full-stack web service orientation, whereas Mule’s capacities as an integration framework open it to all sorts of other protocols. Comprehensive documentation, a subject on which Mule Source has made huge progress recently.

21. What Is Component In Mule?
Answer: Components are the centerpiece of Mule’s services. Each service is organized with a component at its core and inbound and outbound routers around it. Components are used to implement a specific behavior in service. This behavior can be as simple as logging messages or can go as far as invoking other services. Components can also have no behavior at all; in that case, they are pass-through and make the service act as a bridge between its inbound and outbound routers.

22. What Is Fileage Property In File Connector In Mule?
Answer: The file Age property specifies how long the endpoint should wait before reading the file again. For instance, a file Age of 60000 indicates Mule should wait a minute before processing the file again.

23. Why Mule Was Designed?
Answer: Mule’s core was designed as an event-driven framework combined with a unified representation of messages, expandable with pluggable modules. These modules would provide support for a wide range of transports or add extra features, such as distributed transactions, security, or management. The mule was also designed as a programmatic framework offering programmers the means to graft additional behavior such as specific message processing or custom data transformation.

24. What Is Global Endpoint In Mule?
Answer: An endpoint destination that is shared by several routers, it is worth creating a global endpoint. A global endpoint is not typified for inbound or outbound routing, making it usable in many different places in a configuration file. It must be named so it can actually be used in a service, which will reference the global endpoint by its name. A global endpoint can also help clarify the usage of a particular destination.

25. What is Transient Context?

Transient Context: Used for passing values between Mediation primitives within the current flow — either the request flow or the responses flow. The transient context cannot link requests and responses and hence cannot be used across. Used when you want to save an input message before a service invokes call (within a request or response flow). After the services invoke call, the next primitive can create another message by combining the service invoke a response and the original message stored in the transient context.

26. What Is Service Layer In Mule?
Answer: A Mule service is composed of all the Mule entities involved in processing particular requests in predefined manners. A service is defined by a specific configuration. This configuration determines the different elements, from the different layers of responsibility, that will be mobilized to process the requests that it will be open to receive. Depending on the type of input channel it uses, a service may or may not be publicly accessible outside of the ESB.

27. What Are Configuration Builders In Mule?
Mule uses configuration builders that can translate a human-authored configuration file into the complex graph of objects that constitutes a running node of this ESB. The main builders are of two kinds: a Spring-driven builder, which works with XML files, and a script builder, which can accept scripting language files.

28. Why Does An Endpoint In Mule Offer An Address Attribute?
Answer: This allows us to configure a generic endpoint using the Mule 1.x style of URI-based destination addresses instead of the dedicated attributes of the specific endpoint element.

29. What are Batch Jobs in Mule ESB?
Answer: A batch job is a top-level element in Mule which exists outside all Mule flows. Batch jobs split large messages into records which Mule processes asynchronously in a batch job; just as flows process messages, batch jobs process records.

A batch job contains one or more batch steps which, in turn, contain any number of message processors that act upon records as they move through the batch job. During batch processing, you can use record-level variable and MEL expressions to enrich, route or otherwise act upon records.

30. Is Mulesoft a middleware?
Answer: Mule Enterprise Service Bus is a middleware technology that quickly, easily, and securely connects the enterprise. Unlike typical middleware software, Mule as an ESB is a Java-based middleware solution that is easy to use and easy to scale.

31. What are the different types of Web services?
There are mainly two types of web services.

SOAP web services.
REST full web services.
Mule ESB Interview Questions
Mule ESB Interview Questions

32. What is the MuleSoft Anypoint platform and where it will be used?
Answer: MuleSoft Anypoint Platform of integration products is designed to tie both software as a service (SaaS) and on-premises software.

33. How will we identify ESB is needed in a project?

Implementation of ESB is not suitable for all the projects. We should analyze is really ESB is required here or not. You need to analyze by taking below points into consideration:

In the project, require 3 or more applications and services to be integrated and there must be a need to communicate between the applications.

If it is plain of interacting with more applications and Services in the future then we can go with Mule ESB because it is highly scalable.

We need to keep the cost also in mind before going to ESB implementation.

Let us move to the next Mulesoft Interview Questions

34. What is RAML and why we use it?

RAML – REST ful API Modeling Language.

RAML is similar to WSDL, it contains endpoint URL, request/response schema, HTTP methods, and query and URI parameter.

RAML helps the client (a consumer of the service) know, what the service is and what/how all operations can be invoked.

RAML helps the developer in creating the initial structure of this API. RAML can also be used for documentation purposes.

35. What are the advantages of RESTful web services?
Advantages of REST ful Web Services

Fast: RESTful Web Services are fast because there is no strict specification like SOAP. It consumes less bandwidth and resources.

Language and Platform independent: RESTful web services can be written in any programming language and executed in any platform.

Can use SOAP: REST ful web services can use SOAP web services as the implementation.

Permits different data formats: RESTful web service permits different data formats such as Plain Text, HTML, XML, and JSON.

36. What is a Web service API?
Answer: An API (Application Programming Interface) is the means by which third parties can write code that interfaces with other code. A Web Service is a type of API, one that almost always operates over HTTP (though some, like SOAP, can use alternate transports, like SMTP).

37. What Are Available Esbs Apart From Mule?
All major JEE vendors (BEA, IBM, Oracle, Sun) have an ESB in their catalog. It is unremarkably based on their middleware technologies and is usually at the core of a much broader SOA product suite. There are also some commercial ESBs that have been built by vendors not in the field of JEE application servers, like the ones from Progress Software, IONA Technologies, and Software AG.

38. What Is Polling frequency Property In File Connector In Mule?
Answer: When we want to file inbound endpoints to poll their source directories for new content. This is accomplished by setting the polling frequency to some milliseconds value.

39. What Is Multicasting Router In Mule?
Answer: The multicasting router can send messages to multiple endpoints over different transports. The multicasting router allows you to easily move the same messages across these different endpoints.

40. Why Mule ESB?
Answer: Mule ESB is lightweight but highly scalable, allowing you to start small and connect more applications over time. Mule manages all the interactions between applications and components transparently, regardless of whether they exist in the same virtual machine or over the Internet, and regardless of the underlying transport protocol used.

There are currently several commercial ESB implementations on the market. However, many of these provide limited functionality or are built on top of an existing application server or messaging server, locking you into that specific vendor. Mule is vendor-neutral, so different vendor implementations can plug into it. You are never locked in to a specific vendor when you use Mule.

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