Showing posts with label ESB. Show all posts
Showing posts with label ESB. Show all posts

January 04, 2022

Top 20 Apache Camel Interview Questions and Answers


                    The Apache Camel software is a message-oriented middleware system that is free and open source. The mediation takes place according to the guidelines that have been established. It's used by a lot of companies for data processing and analysis. Camel can be thought of as a routing engine at a high level. Camel allows us to establish routing rules for messages to be sent from a specific source to a specified destination.

                    Camel has built-in support for a variety of protocols, making it simple to interconnect diverse systems. Camel can easily integrate two separate apps that function with ftp and jms. Camel handles all of the protocol and datatype conversions for us internally.

 Apache Spark Interview Questions & Answers

Ques. 1): What is Apache Camel, and how does it work?


There are a variety of oscillate systems in an organisation. Some of them could be legacy systems, while others could be new. These systems frequently interact in imitation of one another and require integration. Relationships or integration are more difficult than system implementations because message formats may differ. One method to achieve this is to agree on a code that bridges these gaps. However, there will be a decrease in mitigation integration as a result of this. If there is a fiddle contemplating in a system tomorrow, the press on may have to be tainted, which is not pleasant. Instead of this narrowing to mitigation integration which causes tight coupling, we can espouse a supplementary descent to mediate the differences along surrounded by the systems.

 Apache Hive Interview Questions & Answers

Ques. 2): In Apache Camel, what are EIPs?


EIP (Enterprise Integration Patterns) is the abbreviation for Enterprise Integration Patterns. In the form of a pattern, these are design patterns for the usage of enterprise application integration and message-oriented middleware. Apache Camel makes use of a number of EIPs. Here are a few:

Splitter Pattern: Split the data on the basis of some token and then process it.

Content Based Router: The Content-Based Router inspects the content of a message and routes it to another channel based on the content of the message. Using such a router enables the message producer to send messages to a single channel and leave it to the Content-Based Router to inspect messages and route them to the proper destination. This alleviates the sending application from this task and avoids coupling the message producer to specific destination channels.

Message Filter: A Message Filter is a special form of a Content-Based Router. It examines the message content and passes the message to another channel if the message content matches certain criteria. Otherwise, it discards the message.

Recipient List: A Content-Based Router allows us to route a message to the correct system based on message content. This process is transparent to the original sender in the sense that the originator simply sends the message to a channel, where the router picks it up and takes care of everything.

Wire Tap: Wire Tap allows you to route messages to a separate location while they are being forwarded to the ultimate destination.

 Apache Ambari interview Questions & Answers

Ques. 3): What are Apache Camel Components?


In Apache Camel, a component is a factory or a group of Endpoint instances. When using Spring or Guice, we can explicitly configure Component instances and connect them to a Camel Context in an IoC container. URIs can be used to discover components automatically.

Apache Camel comes with a lot of pre-built components. Some key Camel components from the core module are listed below.

  • Bean
  • Direct
  • File
  • Log
  • SEDA
  • Timer

 Apache Tapestry Interview Questions and Answers

Ques. 4): What is an exchange in Apache camel?


The message that will be routed through the Camel route is already in the Exchange. It's the holder of the message. Message Exchange Patterns are used by Apache Camel (MEP). Any type of communication can be stored in an Apache camel exchange. It accepts a variety of file types, including XML, JSON, and others.

 Apache Kafka Interview Questions and Answers

Ques. 5): What is an ESB? Have you deployed a camel for any ESB?


Enterprise Service Bus (ESB) stands for Enterprise Service Bus. It is a tool that is used to help a severely pained application employing SOA concepts. When projects need integrating a number of Endpoints in front of Webservices, JMS, FTP, and other systems, an optimal unmodified ESB should be employed. JBoss Fuse ESB has been installed for Apache Camel Deployment.

 Apache Tomcat Interview Questions and Answers

Ques. 6): What is a row in the Apache camel?


In the Exchange, the declaration to be routed via the Camel route is a gift. It is the possessor of the statement. Message Exchange Patterns are used by Apache Camel (MEP). Any nice of publication can be retained by Apache camel disputes. It supports a multitude of formats, including XML, JSON, and others.

 Apache Ant Interview Questions and Answers

Ques. 7): What are the apache camel endpoints?


The Endpoint interface in Camel implements the Message Endpoint pattern. Endpoints are usually established by Components, and their URIs are used to refer to them in the DSL.

 Apache NiFi Interview Questions & Answers

Ques. 8): What is Apache JMeter?


JMeter is an Apache project that is used as a load balancing tool to evaluate the performance of a variety of facilities, including the most sophisticated web applications.

JMeter can also be used as a unit-testing tool for JDBC database connections, FTP, Web services, JMS, HTTP, and TCP connections, as well as OS native processes. JMeter can also be configured as a monitor, though this is more of a monitoring tool than a believer control tool, and it can be used for active scrutiny as well. Jmeter also fosters integration when compared to Selenium, allowing it to control automation scripts in addition to performing or load testing.


Ques. 9): What is the Idempotent Consumer pattern in Apache Camel?


We employ the Idempotent Consumer pattern in Apache Camel to filter out duplicate messages. Consider a case in which we must handle files without assistance while taking into account. Duplicates should be skipped if there are any. We may utilise Idempotent Consumer right within the component using Apache Camel, and it will skip files that have already been processed. The environment's idempotent=real choice will enable this feature. To do this, Apache Camel uses a statement-id, which is stored in the Idempotent Repository, to keep track of the consumed files. IdempotentRepository types are provided by Apache Camel.


Ques. 10): How does Apache Camel handle exceptions?


The try> catch> block, the OnException> block, or the errorHandler> block can all be used to handle exceptions.

Any uncaught Exception thrown during the routing and processing of a message is handled by the errorHandler. On the other hand, when certain Exception types are thrown, onException is used to manage them.


Ques. 11): What is CamelContext, and how does it work?


A single Camel routing rulebase is represented by the CamelContext. The CamelContext is comparable to the Spring ApplicationContext in that it is used in the same way. interface for the general public SuspendableService and RuntimeConfiguration are both extended by CamelContext. The context used to configure routes and policies to utilise during message exchanges between endpoints is represented by this interface.


Ques. 12): What is the best way to restart CamelContext?


To govern the camel lifecycle, the camel context provides many methods such as start, stop, suspend, and resume. A service can be restarted using one of two techniques. Stopping the context and then starting it is one option. It's known as a cold restart, and it clears the internal state, cache, and other data to render all endpoints useless. Suspend and resume operations are another option. It saves all of your endpoints so you can use them again after you restart.


Ques. 13): What is an URI?


In camel, a URI is a naming system for referring to an endpoint. An URI informs Camel about the component being used, the context path, and the options that have been applied to it. The URI is made up of three parts:

  • Scheme
  • Context path
  • Options

Example of a file URI working as a consumer –


Here the scheme points to file, the context path is “src/data” and the options are “fileName and fileExist” are options that can be used with file component or file endpoint.


Ques. 14): In Apache Camel, what is the Idempotent Consumer pattern?


We employ the Idempotent Consumer pattern in Apache Camel to filter out duplicate messages. Consider the case where we only need to process messages once. Duplicates should be skipped if there are any. We can utilise Idempotent Consumer directly within Apache Camel to bypass messages that have already been processed. The idempotent=true option is used to enable this feature. To do this, Apache Camel uses a message id, which is stored in the Idempotent Repository, to keep track of the consumed messages. IdempotentRepository is a kind of IdempotentRepository provided by Apache Camel.


Ques. 15): How to connect with Azure from Apache Camel?


Yes. We can connect with azure services using Apache camel connector components.

Maven Dependency:





  <!-- use the same version as your Camel core version -->


Code Example:



Ques. 16): What is a Message in Apache Camel ?


Message implements the Message pattern and represents an inbound or outbound message as part of an Exchange.It contains the data being transferred using Routes- It consists of the following fields-

  • Unique Identifier
  • Headers
  • Body
  • Fault Flag


Ques. 17): What is the relationship between Apache Camel and ActiveMQ?


Apache Camel is embedded in the ActiveMQ broker using the ActiveMQ component. It allows you a lot of versatility when it comes to extending the message broker. Additionally, the ActiveMQ component eliminates the serialisation and network costs associated with connecting to ActiveMQ remotely.

This component is built on the JMS component and allows users to send and consume messages over the JMS Queue.


Ques. 18): How do I disable JMX in Apache Camel?


The JMX instrumentation agent is enabled in Camel by default. To disable the JMX instrumentation agent, set the following property in the Java VM system property,


Another way of disabling is by adding the JMX agent element inside the camel context element in the Spring configuration,

<camelContext id=”camel” xmlns=””>

<jmxAgent id=”agent” disabled=”true”/>




Ques. 19): What Jars Do I Need?

Answer :

Camel is designed to be small lightweight and extremely modular so that you only pay for what you use. The core of camel, camel-core.jar is small and has minimal dependencies.

On Java 6 camel-core.jar only depends on

commons-management.jar (for Camel 2.8 or older)

commons-logging.jar (for Camel 2.6 or older)

slf4j-api.jar (from Camel 2.7 onwards)

On Java 5 camel-core.jar depends also on activation.jar and a JAXB2 implementation which typically involves jaxb-api.jar, jaxb-impl.jar and a StAX API which may be stax-api.jar and *woodstox.jar


Ques. 20): What Is The Difference Between A Producer And A Consumer Endpoint?


A camel route is similar to a data channel in that it transports data. At either end of the channel, there are two endpoints: producer and consumer.

The route's beginning point is called a consumer endpoint. Writing a camel consumer endpoint is the first step in defining a camel route.

A producer endpoint appears at the end of the route (but not always). The data that is passed through the route is consumed by it.