Latest Technical Interview Answers

Latest Technical Interview Answers

What is point-to-point messaging?
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With point-to-point message passing the sending application/client establishes a named message queue in the JMS broker/server and sends messages to this queue. The receiving client registers with the broker to receive messages posted to this queue. There is a one-to-one relationship between the sending and receiving clients.
What is the difference between BytesMessage and StreamMessage??
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BytesMessage stores the primitive data types by converting them to their byte representation. Thus the message is one contiguous stream of bytes. While the StreamMessage maintains a boundary between the different data types stored because it also stores the type information along with the value of the primitive being stored. BytesMessage allows data to be [...]
What is the use of MapMessage?
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A MapMessage carries name-value pair as it’s payload. Thus it’s payload is similar to the java.util.Properties object of Java. The values can be Java primitives or their wrappers.
What is the use of ObjectMessage?
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ObjectMessage contains a Serializable java object as it’s payload. Thus it allows exchange of Java objects between applications. This in itself mandates that both the applications be Java applications. The consumer of the message must typecast the object received to it’s appropriate type. Thus the consumer should before hand know the actual type of the [...]
What is the use of TextMessage?
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TextMessage contains instance of java.lang.String as it’s payload. Thus it is very useful for exchanging textual data. It can also be used for exchanging complex character data such as an XML document.
What is the use of StreamMessage?
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StreamMessage carries a stream of Java primitive types as it’s payload. It contains some conveient methods for reading the data stored in the payload. However StreamMessage prevents reading a long value as short, something that is allwed in case of BytesMessage. This is so because the StreamMessage also writes the type information alonwgith the value [...]
What is the use of BytesMessage?
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BytesMessage contains an array of primitive bytes in it’s payload. Thus it can be used for transfer of data between two applications in their native format which may not be compatible with other Message types. It is also useful where JMS is used purely as a transport between two systems and the message payload is [...]
What is the basic difference between Publish Subscribe model and P2P model?
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Publish Subscribe model is typically used in one-to-many situation. It is unreliable but very fast. P2P model is used in one-to-one situation. It is highly reliable.
What is the use of Message object?
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Message is a light weight message having only header and properties and no payload. Thus if theIf the receivers are to be notified abt an event, and no data needs to be exchanged then using Message can be very efficient.
What is the role of JMS in enterprise solution development?
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JMS is typically used in the following scenarios 1. Enterprise Application Integration: - Where a legacy application is integrated with a new application via messaging. 2. B2B or Business to Business: - Businesses can interact with each other via messaging because JMS allows organizations to cooperate without tightly coupling their business systems. 3. Geographically dispersed units: - JMS [...]
What is the difference between topic and queue?
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A topic is typically used for one to many messaging i.e. it supports publish subscribe model of messaging. While queue is used for one-to-one messaging i.e. it supports Point to Point Messaging.
What are the different messaging paradigms JMS supports?
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Publish and Subscribe i.e. pub/suc and Point to Point i.e. p2p.
What are the different types of messages available in the JMS API?
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Message, TextMessage, BytesMessage, StreamMessage, ObjectMessage, MapMessage are the different messages available in the JMS API.
Are you aware of any major JMS products available in the market?
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IBM’s MQ Series is one of the most popular product used as Message Oriented Middleware. Some of the other products are SonicMQ, iBus etc.All the J2EE compliant application servers come built with thier own implementation of JMS.
What are the advantages of JMS?
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JMS is asynchronous in nature. Thus not all the pieces need to be up all the time for the application to function as a whole. Even if the receiver is down the MOM will store the messages on it’s behalf and will send them once it comes back up. Thus at least a part of [...]
How JMS is different from RPC?
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In RPC the method invoker waits for the method to finish execution and return the control back to the invoker. Thus it is completely synchronous in nature. While in JMS the message sender just sends the message to the destination and continues it’s own processing. The sender does not wait for the receiver to respond. [...]
What are the core JMS-related objects required for each JMS-enabled application?
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Each JMS-enabled client must establish the following: • A connection object provided by the JMS server (the message broker) • Within a connection, one or more sessions, which provide a context for message sending and receiving • Within a session, either a queue or ic object representing the destination (the message staging area) within the message broker • Within [...]
What are the types of messaging?
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There are two kinds of Messaging. Synchronous Messaging: Synchronous messaging involves a client that waits for the server to respond to a message. Asynchronous Messaging: Asynchronous messaging involves a client that does not wait for a message from the server. An event is used to trigger a message from a server.
What is MDB and What is the special feature of that?
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MDB is Message driven bean, which very much resembles the Stateless session bean. The incoming and out going messages can be handled by the Message driven bean. The ability to communicate asynchronously is the special feature about the Message driven bean.
How is a java object message delivered to a non-java Client?
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It is according to the specification that the message sent should be received in the same format. A non-java client cannot receive a message in the form of java object. The provider in between handles the conversion of the data type and the message is transferred to the other end.