Tag: programming languages

Questions Related to programming languages

A transactional client receives TransactionRolledBackException from a call to a method on an entity bean. What could be the possible reason(s) for this?
technology programming languages

  1. The bean method is throwing a checked exception and is configured with a transaction attribute of "Required".

  2. The bean method is throwing an unchecked exception and is configured with a transaction attribute of "Required".

  3. The bean does not throw an exception but is configured with a transaction attribute of "Mandatory".

  4. The bean method is throwing an unchecked exception and is configured with a transaction attribute of "Requires New".

Show answer
Correct Option: B

Your application supports multiple client types including HTTP clients. Your business layer is implemented using Enterprise Java Beans. Which of the following is best suited for maintaining client state?
technology programming languages

  1. Cookies

  2. Entity Beans

  3. HttpSession attributes

  4. Stateful session beans

  5. URL Rewriting

Show answer
Correct Option: D
Explanation:

To maintain client state, the user needs to know the different options available and which option is best suited to the given scenario.

A. Cookies: Cookies are small text files that are stored on the client's computer. They can be used to store client state information, such as user preferences or session IDs. While cookies can be effective for maintaining state, they have some limitations, such as a limited storage capacity and the potential for security vulnerabilities.

B. Entity Beans: Entity beans are used to represent persistent data in a Java Enterprise Edition (JEE) application. They are not designed to maintain client state.

C. HttpSession attributes: HttpSession attributes are used to store client-specific information on the server side. They are associated with a particular user session and can be used to maintain client state across multiple requests. This makes HttpSession attributes a good option for maintaining client state in a JEE application.

D. Stateful session beans: Stateful session beans are designed to maintain state across multiple requests. They are associated with a particular client and can be used to store client-specific information. This makes stateful session beans a good option for maintaining client state in a JEE application.

E. URL Rewriting: URL rewriting is a technique for adding session IDs to URLs. This allows the server to identify the client and maintain state across multiple requests. While URL rewriting can be effective for maintaining state, it has some limitations, such as the potential for security vulnerabilities and the impact on URL readability.

Based on the given scenario, the best option for maintaining client state is D. Stateful session beans, as they are designed to maintain state across multiple requests and are associated with a particular client. Option C. HttpSession attributes is also a good option since it can be used to maintain client state across multiple requests. Option A. Cookies and option E. URL Rewriting can also be used to maintain state but are less suited to the given scenario.

The Answer is: D. Stateful session beans

Which enterprise bean type is defined without any client view interfaces?

technology programming languages

  1. BMP Entity bean

  2. CMP Entity bean

  3. Stateful Session bean

  4. Stateless Session bean

  5. Message Driven Bean

Show answer
Correct Option: E

AI Explanation

To answer this question, we need to understand the different types of enterprise beans in Java EE.

Option A) BMP Entity bean - This option is incorrect because BMP (Bean-Managed Persistence) Entity beans do have a client view interface.

Option B) CMP Entity bean - This option is incorrect because CMP (Container-Managed Persistence) Entity beans also have a client view interface.

Option C) Stateful Session bean - This option is incorrect because Stateful Session beans have a client view interface.

Option D) Stateless Session bean - This option is incorrect because Stateless Session beans also have a client view interface.

Option E) Message Driven Bean - This option is correct because Message Driven Beans are the only type of enterprise beans that can be defined without any client view interfaces. Message Driven Beans are used for asynchronous processing of messages received from a messaging system.

Therefore, the correct answer is option E) Message Driven Bean.

Which of the following is NOT an advantage of using the SessionFacade pattern?

technology programming languages

  1. Hides model complexity from the client

  2. Reduces network traffic

  3. Provides a simple interface to the client

  4. Enables the client to control transactions

Show answer
Correct Option: D

AI Explanation

To answer this question, you need to understand the SessionFacade pattern and its advantages. Let's go through each option to understand why it is correct or incorrect:

Option A) Hides model complexity from the client - This option is correct. One of the advantages of using the SessionFacade pattern is that it hides the complexity of the underlying model from the client. The client only needs to interact with the simplified interface provided by the SessionFacade.

Option B) Reduces network traffic - This option is correct. Another advantage of using the SessionFacade pattern is that it can help reduce network traffic. By encapsulating multiple operations into a single method call, the SessionFacade can minimize the number of network requests required.

Option C) Provides a simple interface to the client - This option is correct. The SessionFacade pattern provides a simple interface to the client. Instead of having to interact with multiple components or services directly, the client can use the SessionFacade as a single entry point for its operations.

Option D) Enables the client to control transactions - This option is incorrect. The SessionFacade pattern does not enable the client to control transactions directly. Instead, it encapsulates the transaction management logic within the SessionFacade itself. The client interacts with the SessionFacade, but it does not have control over the transaction boundaries.

The correct answer is D) Enables the client to control transactions. This option is incorrect because the SessionFacade pattern does not provide this advantage.

You want to locate an existing bean object but do not want to create a new instance, if an existing instance is not available. Which of the following bean attributes will you use in the jsp:useBean action?
technology programming languages

  1. class

  2. type

  3. beanName

  4. class and type

  5. beanName and type

Show answer
Correct Option: B

A container-managed persistence (CMP) entity bean A has a one-to-many unidirectional relationship (CMR) to another container-managed persistence (CMP) entity bean B. Which interface can expose the methods related to this relationship?

technology programming languages

  1. Only local interface of bean A

  2. Local interfaces of both beans A and B

  3. Only local home interface of bean A

  4. Local home interfaces of both beans A and B

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Correct Option: A

Which method cannot be called by a stateful session bean using bean-managed transactions?
technology programming languages

  1. getUserTransaction()

  2. getRollbackOnly()

  3. getStatus()

  4. None of these

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Correct Option: B

Which of the following statements are true about the given method declaration? MyEJBObject createWithName(String name) throws CreateException, RemoteException
technology programming languages

  1. It is declared in the local home interface of a stateful session bean.

  2. It is declared in the local home interface of a stateless session bean.

  3. It is declared in the remote home interface of a stateful session bean.

  4. It is declared in the remote home interface of a stateless session bean.

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Correct Option: C

Select all correct statements.
technology programming languages

  1. EJBs are not allowed to open a socket to connect to a FTP server and download a document.

  2. EJBs are not allowed to log an error to a file on disk.

  3. EJBs are allowed to install a new security manager when they have to perform highly secure jobs.

  4. EJBs are allowed to invoke Class.getResource in order to retrieve bundled resources (images, texts, properties, etc).

  5. EJBs are allowed to create small java.awt.Window components in order to display business processing errors or exception messages.

  6. EJBs are allowed to spawn their own threads in order to perform some time-consuming tasks, for example.

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Correct Option: B,D

Which of the following combinations (Design Pattern - Functionality) regarding Design Patterns is correct?
technology programming languages

  1. Business Delegate - Reduces the coupling between presentation-tier clients and business services.

  2. Data Access Object - Multiple View using the same model.

  3. MVC - Enables easier migration to different persistence storage implementation.

  4. Value Object - Reduces Network Traffic

Show answer
Correct Option: D