Interview Questions.

Q1. What Optimization Could I Use If The Ejb Container Is The Only Point Of Write Access To The Database?

You may want to spark off the “Commit Option A” that is the box caches entity bean country among tractions. This choice assumes that the box has one of a kind get admission to to the continual store and consequently it doesnt want to synchronize the in-reminiscence bean kingdom from the continual store at the start of each traction.

Q2. What Do You Know About Seam?

Built on the standards Java Server Faces and EJB three.Zero, JBoss Seam unifies component and programming models and delivers a regular and effective framework for rapid creation of web programs with Java EE 5.@Seam simplifies internet software development and allows new functionality that turned into tough to implement by using hand before, consisting of stateful conversations, multi-window operation, and dealing with concurrent pleasant-grained AJAX requests. Seam additionally unifies and integrates popular open source technologies like Facelets, Hibernate, iText, and Lucene.

Q3. What Version Of Jboss As Do I Need To Run Seam?

For Seam 1.Three: Seam changed into evolved in opposition to JBoss four.@Seam can nonetheless be run against JBoss 4.@The seam documentation contains commands for configuring JBoss four.Zero.

For Seam 1.2: Since Seam calls for the latest edition of EJB3, you need to install JBoss AS from the latest JEMS installer. Make certain which you choose the “ejb3” or “ejb3+clustering” profile to include EJB3 aid. Also, the jboss-seam.Jar library record from the Seam distribution should be protected in every Seam application you set up. 

Q4. Can I Unit Test Seam Applications Without Starting The Application Server?

Yes, Seam offers its personal integration test framework based on TestNG. You can without problems mock all Seam services the use of those facilities with out ever loading an software server or a database. 

Q5. What Are The File Types You Can Deploy In Jboss?

You can install nearly any type of Java/J2EE software, and it helps the subsequent report format.

WAR: Web application archive

SAR: Service archive

JAR: Java Archive

EAR: Enterprise utility archive

Q6. Do You Know How You Could Add Support For Web Service Tractions?

JBossTS supports Web Services tractions, including extended traction fashions designed in particular for loosely-coupled, long jogging enterprise procedures. J2EE tractions can combine seamlessly with Web Services tractions using our included, bi-directional traction bridge. Interoperability with many different vendors is furnished out-of-the-field and JBoss is an active player in these requirements.

Q7. What Is Difference Between <validate-on-match> And <background-validation>?

<validate-on-match> validate the database connection each time, and if a connection isn't always valid, it'll write a warning inside the logs.

Having “validate-on-match” configured may additionally have a bit high load at the database as it is able to create lots of requests.

<background-validation> validate the connection periodically primarily based on what frequency is configured for “background-validation-millis”. The default configuration is about to zero me disabled.

Having “ history-validation” set to authentic will create fewer database connections and it’s aspect-outcomes might be now not detecting without delay if useless connections.

Q8. How Do You Look Inside A Jar File?

 Jar –tf <filename.Jar>

Q9. How Can You Start A Jta Traction From A Servlet Deployed On Jboss?

JBoss registers within the JNDI tree a JTA UserTraction Object which may be person to control a disbursed traction.

Q10. Can I Run Seam Outside Of Jboss As?

Yes, you may run Seam applications in undeniable Tomcat 5.Five+ or inside the Sun GlassFish software server. To run Seam application in Tomcat, you want a number of extra library documents and a few configuration files to bootstrap the JBoss EJB3 interior Tomcat.

Q11. Does Seam Run On Other Application Servers Besides Jboss?

Seam runs beautifully on other utility servers – just like the whole lot else the Hibernate team does, this is not a JBoss-only aspect.

Q12. What Is The Difference Between Hibernate And Ejb three? Do Not You Think Ejb three Is Just A Clone Of Hibernate?

The perception of EJB3 as being a easy identical to Hibernate is based on developer familiarity with Hibernate and a similarity of naming, in addition to not unusual reason, and that Hibernate is morphing itself into an EJB3 implementation primarily based on the work going into the specification, not the opposite manner round.

EJBs are purported to be additives, in the feel that they’re now not simply one elegance, however a set of lessons, descriptors and usage and control contracts. All of this with the intention to allow a field (JBoss, Weblogic, and many others.) to offer services to the ones additives, and so as to reuse and distribute this components. This offerings are, among others, tractions, concurrent get admission to manipulate, protection, instance pooling, etc.

Hibernate is “simply” an ORM (Object/Relational Mapping) device. Quick and grimy, this me you can store an item tree belonging to an magnificence hierarchy in a relational DB without writing a unmarried SQL query. Quite cool, IMO. But no traction manage, no instance pooling, no concurrency control, and truely no safety.

Q13. What Is Jboss Jbpm?

JBoss JBPM is a workflow and BPM engine. Enabling the advent of enterprise procedures that coordinates between human beings, programs and offerings is the capability of BPM engine. The combination of workflow programs development with system design is a feature of JBoss jBPM. The commercial enterprise system is graphically represented to facilitate a strong link between the business analyst and technical developer. This function is furnished by using the JBoss jBPM technique clothier.

Q14. What Module Needed To Integrate Apache With Jboss?

There are  modules you may use to attach JBoss with Apache.

Mod_proxy.

Mod_jk.

Q15. Which Hibernate Object Wraps The Jdbc Connection?

The Session interface wraps a JDBC Connection. This interface is a unmarried threaded object which represents a unmarried unit of work with software and continual database. It’s retrieved through the SessionFactory’s openSession() technique

Q16. Is The Session Factory Thread Safe?

Yes, this is many threads can get admission to it concurrently and request for classes. It holds cached data that has been examine in a single unit of labor and may be reused in a future unit of work. Good exercise is to create it whilst the software is initialized.

Q17. What Is The Difference Between A Local-tx-datasource And A Xa-datasource? Can You Use Tractions In Both?

A nearby-tx-datasource identifies a records source that uses tractions, even disbursed tr moves within the local utility server, however doesnt use disbursed tractions amongst multiple application servers. An xa-datasource then again identifies a information source that makes use of disbursed traction amongst more than one utility servers.

Q18. Which Component Is Responsible For Handling Clustering?

JBoss clustering is on pinnacle of JGroups toolkit which allows to create, delete, membership detection, notification, etc. In the cluster.

Q19. How Would You Convince My It Department To Adopt Soa?

In my opinion one in all the most important impediment within the movement towards SOA adoption is the employer own IT branch.Too many humans inside the IT corporation conceive SOA as a generation concept handiest, and as such consider SOA as just a set of technology and infrastructure for exposing, securing, going for walks, and coping with Services.

Put it this way, SOA is nothing extra than Web Services and standardized middleware. The essential flaw in wondering is puzzling the technology that sits below the Services stage of abstraction and the mechanism via which Services are accessed with the architectural approach that targets to decouple the implementation from the consumption and recognition on sustainable structure that permits for non-stop alternate.

Successful SOA adoption requires a cultural shift within the manner IT is performed. The Service-oriented movement to agility and free coupling needs a shift from traditional, waterfall sorts of improvement (layout-build-check-set up-manage) to iterative processes to non-stop Service modeling

Q20. How To Install Jboss On Linux Server?

JBoss set up is very sincere. You want to down load the favored model from JBoss reliable download page in zip or gz layout.

Once downloaded, just extract the document to the area you need to install. If you downloaded zip format, then you may use unzip command to extract it.

Unzip jboss-as-7.1.1.Final.Zip

Q21. How Do You Perform A Hot Deployment?

JBoss has a integrated hot deployer which can:

Detect new programs in the installation folder and trigger an software deployment

Detect an utility which changed into eliminated from the install folder and trigger an utility undeployment

Detect that the deployment descriptor of an utility (for instance, the web.Xml of .Warfare or software.Xml of .Ear) has modified and cause an application redeployment

Q22. Where Can I Find Seam Examples And Documentation?

The supply code and build script of all Seam instance applications are blanketed inside the examples listing of the Seam distribution.

Q23. Which Component Handles Cluster Communication In Jboss?

The JGroups framework presents services to permit peer-to-peer communications among nodes in a cluster. It is built on pinnacle a stack of community conversation protocols that offer trport, discovery, reliability and failure detection, and cluster club management offerings.

Q24. What Is Jta?

Java Traction API (JTA) specifies wellknown Java interfaces between a traction supervisor and the events concerned in a disbursed traction gadget: the resource manager, the software server, and the tractional applications.

The Javaâ„¢ Traction API (JTA) permits packages to perform dispensed tractions, this is, tractions that get right of entry to and replace statistics on  or more networked laptop sources.

The Java Traction API consists of three factors: a high-level application traction demarcation interface, a excessive-stage traction manager interface supposed for an application server, and a widespread Java mapping of the X/Open XA protocol meant for a tractional aid manager.

Q25. What Is The Directory Structure In Jboss?

The following directories are available after JBoss is hooked up.

Modules

bundles

domain

standalone

appclient

bin

doctors

welcome-content

Q26. How Do You Enable/disable A Hot Deployment?

To enable, placed record hdscanner-jboss-be.Xml in  JBOSS_HOME/server/<profilename>/install

To disable warm deployment, dispose of the hdscanner-jboss-be. Xml from the install folder or rename it to hdscanner-jbossbe. Xml.Bak (.Bak files are not noted).

Q27. Can I Use Ajax With Seam?

Yes, Seam affords extraordinary aid for AJAX. First, Seam helps the ICEfaces and Ajax4JSF Ajax aspect libraries for JSF. If you prefer a extra “old skool” approach, Seam offers a whole JavaScript remoting framework which lets you name Seam components and enroll in JMS subjects immediately from the consumer. 

Q28. How Can You Deploy An Application?

There are three feasible approaches to installation an utility in JBoss utility server.

Admin Console – you can installation the essential application documents thru the management console.

Auto-deploy – leverage report gadget deployment scanner to car install documents from deployments folder.

Automation – use automation tool/ant/scripting to set up an software.

Q29. What Is Jboss?

JBoss is a famous open source software server based on JEE generation. Being JEE based, the JBoss helps pass-platform java programs. It became embedded with Apache Tomcat internet server. It runs underneath any JVM of 1.Three or later versions. JBoss supports JNDI, Servlet/JSP (Tomcat or Jetty), EJB, JTS/JTA, JCA, JMS, Clustering (JavaGroups), Web Services (Axis), and IIOP integration (JacORB).

Q30. How To Increase Java Heap Memory In Jboss 7?

Heap Memory can be expanded in a respective conf document. To boom reminiscence for standalone;

Go to bin folder

Edit the standalone.Conf file and look for “JAVA_OPTS=” argument line

The default configuration may have minimal sixty four MB and maximum 512 MB. You can growth to the desired cost.

Xms – specify the minimum heap length.

Xmx – specify the maximum heap length.

In a similar manner, you could regulate the reminiscence for a domain in domain.Conf file

Q31. Can I Run Seam In A J2ee Environment?

Yes, as of Seam 1.1, you may use Seam in any J2EE software server, with one caveat: you will now not be capable of use EJB three.Zero consultation be. However, you can use either Hibernate or JPA for endurance, and you may use Seam JavaBean additives in preference to session be.

Q32. What Do You Think About Bpel And Bpm ? How Do They Compare?

BPEL and BPM are pretty various things so they can't also be in comparison. The problems boils all the way down to the reality that those years perhaps BPEL has been marketed for something which isn’t: that is a Business Process Management framework.

BPEL is made up for service orchestration, this is publishing new services as a characteristic of different services.

While BPM si wished for dealing with human undertaking control functionalities and subprocess management.

Q33. What Is Jboss Eap?

JBoss Enterprise Application Platform is an open supply implementation of the Java EE suite of offerings

Q34. What Are The Differences Between Ejb 3.Zero And Ejb 2.Zero?

EJBs are actually simple antique Java objects (POJO) that reveal ordinary business interfaces (POJI), and there may be no requirement for domestic interfaces.

Use of metadata annotations, an extensible, metadata-pushed, attribute-orientated framework this is used to generate Java code or XML deployment descriptors.

Removal of the requirement for unique interfaces and deployment descriptors (deployment descriptor facts may be changed by using annotations).

Interceptor facility to invoke person techniques at the invocation of commercial enterprise methods or at life cycle events.

Default values are used on every occasion feasible.

Reduction inside the necessities for utilization of checked exception.

A complete new endurance model (based totally on the JPA preferred), that supersedes EJB 2.X entity be

Q35. What Marker File Type Is Required To Instruct Jboss To Deploy?

.Dodeploy report suffix is wanted for JBoss to installation or redeploy an utility.

For ex: myfirstapplication.Warfare.Dpdeploy

Q36. What Does Mgmt-user.Properties Contain?

All admin console users and password (encrypted) are stored in mgmt.-consumer.Houses file.

Q37. Can You Create A Cluster In Standalone Mode?

Yes, clustering is possible in standalone mode. However, an application ought to be deployed on every server/JVM in standalone mode.

Q38. How To Start Jboss In Standalone Mode?

Go to bin folder in which JBoss is hooked up and start with the following command.

./standalone.Sh

Q39. Which Jdk Is Needed To Run Seam?

Seam handiest works on JDK five.0 and above. It makes use of annotations and different JDK five.Zero capabilities.

Q40. What Must Be Done To Access Admin Console?

The person need to be created under “ManagementRealm” to have console operational. To create the person, you may visit bin folder and execute upload-person.Sh script.

Q41. What If You Need To Span Your Traction Across Multiple Servlet Invocations?

You can’t with a Servlet. A JTA traction have to begin and end within a single invocation (of the provider() method). You need to don't forget the usage of a Stateful SB. In a SFSB with a JTA traction, the affiliation among the bean instance and the traction is retained across a couple of customer calls.

Q42. Is It True That Seam Only Works With Jsf?

Seam simplest helps JSF as a view framework at this time. We plan to support other internet frameworks within the destiny. We like JSF as it is a part-based totally UI framework, which fits absolutely well with Seam’s thing-based totally approach to enterprise items and endurance items. Seam made a major development to JSF by casting off nearly all XML configuration for backing be — you can now define again be from POJOs or EJB3 components the use of simple annotations.

We recommend you operate Facelets, rather than JSP, with JSF. Facelets offer a effective templating framework, higher appplication performance, and lets in us to put in writing a great deal easier JSF pages. Please see the Seam reserving instance software for an instance on the way to use Facelets.

Q43. How Do You Deploy An Application To Jboss?

 Choose the server profile to that you need to set up the software

Copy your software (for example: .Struggle or .Ear or a .Jar record) to JBOSS_HOME/server/<profilename>/set up folder.

Start the server: (./run.Sh)

JBoss will installation your utility when it boots up.

Q44. What Is A .Battle, .Ear Or A .Jar File??

WAR – web software archive is a jar file used to distribute a collection of JavaServer Pages, Java Servlets, Java classes, xml documents, tag libraries, static net pages (html & others) and others assets that constitute a web utility.

JAR – Java Archive, is an archive record layout commonly used to mixture many Java elegance files and related metadata and assets into one report to distribute software software program, libs on the Java platform.

EAR – Enterprise Archive is used to package deal one or more moduels right into a single archive so the deployment of the numerous modules into app server take place simultaneiously and coherently.

Q45. What Are The Logging Levels Available?

There is five possible level:

FATAL

ERROR

WARN

INFO

DEBUG

Q46. What Is The Difference Between Standalone And Domain Mode?

Standalone mode is unmarried JVM technique in which every JBoss server has its configuration. If you simply want one JVM or improvement environment, then standalone might be best.

Domain mode may additionally have multiple servers where all configuration is managed centralized and regularly used in manufacturing surroundings.

Q47. Is It Possible To Put A Jboss Server Instance Into Multiple Cluster At The Same Time?

It is technically viable to position a JBoss server example into multiple clusters on the identical time, this exercise is commonly now not encouraged, as it will increase the management complexity.

Q48. What Are The Important Types Available For Marker File Deployment?

.Dodeploy – train to deploy

.Deployed – imply the file is deployed

.Pending – deployment continues to be pending

.Undeployed – affirmation that application is undeployed

.Failed – deployment is failed for some cause

.Skipdeploy – train JBoss to ignore the documents for auto-deployment

Q49. How Do You Monitor Jboss And Detect The Bottleneck Of An Application?

Different additives of the software are to be measured. This step is to locate in which the degradation is, whether it's miles external or inner and where is the software spending all of the time. Using Jboss JMX retailers and monitoring the deployed additives to the software server involves in the first step.

After finding the maximum of the time spent via precise additives or libraries or maximum of the assets, you will use Jprobe a specialised device for inspecting the single item or the items loaded within the reminiscence.

Q50. What Is Jboss Cache In Short?

JBoss cache is a product. Frequently accessed Java gadgets are cached by using utilzing JBoss cache to enhance the overall performance of e-business packages. JBoss decreases the network traffic and increases the scalability of programs by way of doing away with needless database get admission to. Fully tractional capabilities and quite configurable set of options which can be to address concurrent statistics get entry to, are furnished by JBoss cache in an green manner feasible for the packages.