Weblogic Interview Questions and Answers, Weblogic Interview Questions and Answers Freshers, Weblogic Interview Questions and Answers, Weblogic Interview Questions
Before getting on to the Weblogic interview questions, the student must know that the Weblogic is a continuously varying field which needs the students as well as professionals to upgrade their skills with the new features and knowledge, to get fit for the jobs associated with Weblogic. This post related to Weblogic Interview Questions and Answers, Weblogic Interview Questions and Answers Freshers, Weblogic Interview Questions and Answers, Weblogic Interview Questions will help you let out find all the solutions that are frequently asked in you upcoming Weblogic interview.
Over thousands of vacancies available for the Weblogic developers, experts must be acquaintance with all the component of Weblogic technologies. This is necessary for the students in order to have in-depth knowledge of the subject so that they can have best employment opportunities in the future. Knowing every little detail about Weblogic is the best approach to solve the problems linked with problem.
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Hence, if you are looking for boosting up your profile and securing your future, Weblogic will help you in reaching the zenith of your career. Apart from this, you would also have a lot of opportunities as a fresher.
These questions alone are omnipotent. Read and re-read the questions and their solutions to get accustomed to what you will be asked in the interview. These Weblogic interview questions and answers will also help you on your way to mastering the skills and will take you to the giant world where worldwide and local businesses, huge or medium, are picking up the best and quality Weblogic professionals.
This ultimate list of best Weblogic interview questions will ride you through the quick knowledge of the subject and topics like WLST, Configuring Managed Servers, Configuring Node Managers. This Weblogic interview questions and answers can be your next gateway to your next job as a Weblogic expert.
These are very Basic Weblogic Interview Questions and Answers for freshers and experienced both.
Q1: Explain deployment descriptors?
A1: Deployment descriptors are associated with almost all the modules as well as applications. The deployment descriptors can be seen in the form of XML documents, and they are capable of describing the contents that are part of the directory or the jar file. J2EE specifications usually define the standard as well as the deployment descriptors which are portable for J2EE applications and modules.
Q2: What is web.xml ?
A2: Web.xml is an XML document that is mainly for application purpose and it helps in listing out the J2EE components and configuration that of your application in J2EE modules format.
Q3: What is the name of default JVM that is made used for WebLogic?
A3: The sun hotspot JDK default is made used for development, JRockit is the one used for production of WebLogic 11g as well as 12c. Operating system is another factor that helps in choosing the certified JDK JVM.
Q4: Explain the methods for providing user credentials for starting the server?
A4: At the time of the creation of domain, the wizard for setting configuration asks for the details like user name, password etc. from the user who is logging in for the first time as an administrator. If the domain is created in development mode, the configuration wizard saves the encrypted password as well as the username inside an identity file. This file is available for reference during the time of booting so that in the absence of this file, system can prompt the user for the purpose of entering credentials. A new boot – identity file can be created if you want to change the use credentials or else if you are having the requirement of creating domain in the production mode.
Q5: Is there any possibility for starting managed server during the absence of administrator server?
A5: The usual process is that in case of any difficulty for the manager server to get connected to any administration server at the time of start up, there is an option for the managed server to retrieve the configuration related to it from the configuration files as well as other files involved. The information thus retrieved cannot be altered and it is possible only when the administration server is really available. When the administration server is unavailable, then the managed server enters into its independence mode for carrying out its operations.
Q6: Explain WebLogic server.
A6: This is a kind of server that supports various services as well as infrastructure that are related with JEE applications. WebLogic server is capable of deploying components as well as applications through WSDL, UDDI and SOAP. This server gets configured as a web server by making use of HTTP listener for supporting the HTTP. Web servers like that of Apache, Netscape and Microsoft are utilized. The configuration of a web server allows WebLogic is capable of providing services to dynamic and static requests that are usually generated by servlets, HTML and JSP.
Q7: What are the capabilities of WebLogic server?
A7: There are various capabilities associated with WebLogic server and they are
- Changes in dynamic configuration.
- Production application redeployment
- Rolling upgrades.
Q8: What Is The Managed Server?
A8: Managed server is a server in a domain that is not the Administration server. It contacts the administration server for configuration information. It runs business application in a production environment. It is independent of all other Managed servers in a domain (unless they are not in a cluster). You can have many managed servers in a domain. Individual managed servers are typically added for capacity and application isolation.
Q9: How Administration Server And Managed Servers Will Interact?
A9: The Administration Server stores the master copy of the domain configuration, including the configuration for all Managed Servers in the domain. Each Managed Server stores a local copy of the domain configuration file. When a Managed Server starts, it connects to the Administration Server to synchronize the configuration. When the configuration is changed, the Administration Server sends the changed configuration to the Managed Servers.
Q10: What Is The Msi Mode In Weblogic? How Can You Enable And Disable This Option?
A10: MSI is nothing but Managed Server Independence. By default, Managed Servers can function independently of the Administration Server. A Managed Server instance can start in MSI mode if the Administration Server is unavailable. Configure MSI mode from the Administration Console.To start a Managed Server in MSI mode, perform the following:
Ensure that the Managed Server’s root directory contains the config subdirectory. If the config subdirectory does not exist, copy it from the Administration Server’s root directory.Start the Managed Server at the command line or by using a script.
Environment > Servers > Server_Name > Tuning > Advanced > Managed Server Independence Enabled check box
Q11: Difference Between Weblogic Development And Production Mode?
A11: Here are some difference between Weblogic Development Mode and Production Mode:
1) The default JDK for development domain is Sun Hotspot
2) You can use the demo certificates for SSL
3) Auto deployment is enabled
4) Server instances rotate their log files on startup
5) Admin Server uses an automatically created boot.properties during startup
6) The default maximum capacity for JDBC Datasource is 15
1) The default JDK for production domain is JRockit
2) If you use the demo certificates for SSL a warning is displayed
3) Auto deployment is disabled
4) Server instances rotate their log files when it reaches 5MB
5) Admin Server prompts for username and password during startup
6) The default maximum capacity for JDBC Datasource is 25
Q12: How To Change From Development Mode To Production Mode In Weblogic 10.3?
A12: To change Weblogic start up mode from DEV to production. One way to change it is, by simply editing setDomainEnv.cmd which resides in $root_domain/bin folder.
- Look for the line that sets the PRODUCTION_MODE script variable: set PRODUCTION_MODE
Add false to the value of the PRODUCTION_MODE variable to ensure the server starts in development
Set true for starting in prod mode.
- Save your changes and exit the text editor.
Q13: What Are The Supported Installation Modes For Weblogic Server?
- Graphical mode
- Console mode
- Silent mode
Q14: What Is The Default Port Of Weblogic Admin Server?
A14: By default weblogic admin server configured on port 7001 and SSL is on 7002.
Q15: What Is Boot.proerties File In Weblogic Server?
A15: boot.properties is the file used by admin or managed server during startup for username and password. it exist under your domain/servers/server_name/security folder.
Q16: How many types of weblogic installation ?
A16: There are 3 types of weblogic installation.
(a) Grapical Mode (interactive GUI based)
(b) Console Mode (interactive Text Based)
(c) Silent Mode ( Non Interactive method using .xml properties file)
Q17: How does Cluster Communication Happen?
A17: Members of the Cluster communicate over the Cluster Multicast IP and Port by sending periodic heart beat messages.
Q18: What is the difference between the Sun JVM and BEA JRockit JVM?
A18: The most well know JVM is the implementation from Sun. The Sun JVM is called HotSpot. The Sun JVM is shipped in the Java Developer’s Kit (JDK) and Java Runtime Environment (JRE) from Sun.
The BEA JRockit JVM from BEA systems is optimized for reliability and performance for server side applications. To achieve this, BEA JRockit JVM uses technologies such as code generation, hot spot detection, code optimization, advanced garbage collection algorithms and tight operating system integration.
Q19: What are JVM Tuning Parameters.
A19: If you have a single processor, single thread machine then you should use the serial collector (default for some configurations, can be enabled explicitly for with -XX: +UseSerialGC). For multiprocessor machines where your workload is basically CPU bound, use the parallel collector. This is enabled by default if you use the -server flag, or you can enable it explicitly with -XX:+UseParallelGC. If you’d rather keep the GC pauses shorter at the expense of using more total CPU time for GC, and you have more than one CPU, you can use the concurrent collector (-XX:+UseConcMarkSweepGC).
Q20: How do you do performance tuning of WLS? What are various areas to do it
a. Application Tuning.
jsp precompilation, ejb pool size cache..
b. OS Tuning
Setting tcp ip parameter.
c. Core Server Tuning.
tune work manager, tune chuck size and chunk pool size, using performance packs, connection backlog buffering.
d. JVM Tuning
tuning gc strategy, monitoring garbage collection..
Q21: How do stubs work in a WebLogic Server cluster?
A21: Clients that connect to a WebLogic Server cluster and look up a clustered object obtain a replica-aware stub for the object. This stub contains the list of available server instances that host implementations of the object. The stub also contains the load balancing logic for distributing the load among its host servers
Q22: What is HTTP tunneling? How can we configure it on WebLogic?
A22: HTTP tuning provides a way to simulate a tasteful socket connection between WebLogic Server and a Java client when your only option is to use the HTTP protocol. It is
generally used to tunnel through an HTTP port in a security firewall. HTTP is a stateless protocol, but WebLogic Server provides tunneling functionality to make the connection appear to be a regular T3Connection.
Steps to configure Http tunneling.
- Login into the Admin Console, click on the server on which you want to enable he Http
- Tunneling feature
- Click on the Protocols tab
- check the “Enable Tunneling” check box.
Now you can communicate with the JVMs (Server Instances) using protocols other than t3
Q23: What is the difference between T3 and HTTP protocol?
A23: WebLogic uses the T3 protocols for internal and external connections to the servers. The T3 protocol often is used in WebLogic’s implementation of RMI. Proprietary of WebLogic Server.
Http protocols are used primarily for HTTP communication between the browser and the web server. Standard follows the W3C (World Wide Web Consortium).
Note: All of these protocols are, by default, multiplexed over the same connection to the server’s address and port. So you can access a web page hosted by the server using a URL such as http://host:port/page.jsp. An external client can set up an initial JNDI context to a server using the URL t3://host:port/. All that has changed is the protocol over which the client must communicate with the server.
Q24: What is the default port of Weblogic admin server?
A24: By default weblogic admin server configured on port 7001 and SSL is on 7002.
Q25: How many admin consoles possible in a single domain?
A25: Only One
Q26: What is boot.proerties file in weblogic server?
A26: boot.properties is the file used by admin or managed server during startup for username and password. it exist under your domain/servers/server_name/security folder.
Q27: What is config.xml?
A27: config.xml is the central configuration repository for a domain. every resource you have configured from admin console or by command line or by any other tool registered under this file. WLS 9.x onwards, this file contain references to other xml configuration files also those are under your domain/config folder ( further sub folder under it for respective resources ).
Q28: How do I provide User credentials for starting weblogic server?
A28: When you create a domain, the Configuration Wizard prompts you to provide the username and password for an initial administrative user. If you create the domain in development mode, the wizard saves the username and encrypted password in a boot identity file. A WebLogic Server instance can refer to a boot identity file during its startup process. If a server instance does not find such a file,it prompts you to enter credentials.
If you create a domain in production mode, or if you want to change user credentials in an existing boot identity file, you can create a new boot identity file.
Q29: Can I start a Managed Server if the Administration server is unavailable?
A29: By default, if a Managed Server is unable to connect to the specified Administration Server during startup, it can retrieve its configuration by reading a configuration file and other files directly. You cannot change the server’s configuration until the Administration Server is available. A Managed Server that starts in this way is running in Managed Server Independence mode.
Q30: What Is a WebLogic Server Cluster?
A30: A WebLogic Server cluster consists of multiple WebLogic Server server instances running simultaneously and working together to provide increased scalability and reliability. A cluster appears to clients to be a single WebLogic Server instance. The server instances that constitute a cluster can run on the same machine, or be located on different machines. You can increase a cluster’s capacity by adding additional server instances to the cluster on an existing machine, or you can add machines to the cluster to host the incremental server instances. Each server instance in a cluster must run the same version of WebLogic Server.
Q31: When should I use the -nostage option?
A31: Set the staging mode to -nostage (using weblogic.Deployer or the Administration Console) if you don’t want to copy deployment files but want to deploy an application from its present location. All target servers must be able to access the same set of deployment files.
Q32: When should I use the external_stage option?
A32: Set -external_stage using weblogic.Deployer if you want to stage the application yourself, and prefer to copy it to its target by your own means.
Q33: Can I set the deployment order for application modules? For standalone modules?
A33: The Load Order attribute controls the deployment order of standalone modules and applications relative to other modules and applications of the same type. For example, standalone EJBs with smaller Load Order values are deployed before those with higher values. Modules that are deployed as part of an Enterprise Application (EAR file or directory) are deployed in the order in which they are specified in the application.xml deployment descriptor. What is the difference between the WL_HOME/config/examples/applications folder and the WL_HOME/config/examples/stage folder? The applications folder is intended for applications that are not yet ready for a production environment. WebLogic Server dynamically deploys the contents of the applications folder. The stage folder (or a folder that you create for the same purpose) is for storing copies of deployment files that are ready for deployment in a production environment (deployments that use the stage or external_stage deployment modes).
Q34: How do I turn the auto-deployment feature off?
A34: The auto-deployment feature checks the applications folder every three seconds to determine whether there are any new applications or any changes to existing applications and then dynamically deploys these changes. The auto-deployment feature is enabled for servers that run in development mode. To disable auto-deployment feature, use one of the following methods to place servers in production mode:
- In the Administration Console, click the name of the domain in the left pane, then select the Production Mode checkbox in the right pane.
- At the command line, include the following argument when starting the domain’s Administration Server: -Dweblogic.ProductionModeEnabled=true
Production mode is set for all WebLogic Server instances in a given domain.
Q35: Must EJBs be homogeneously deployed across a cluster? Why?
A35: Yes. In WebLogic Server 6.0 and later, EJBs must be homogeneously deployed across a cluster for the following reasons:
- To keep clustering EJBs simple
- To improve performance by avoiding cross-server calls. If EJBs are not deployed on all servers, cross-server calls are more likely.
- To ensure that every EJB is available locally
- To ensure that all classes are loaded in an undeployable way. Every server must have access to each EJB’s classes so that it can be bound into the local JNDI tree. If only a subset of the servers deploys the bean, the other servers will have to load the bean’s classes in their respective system classpaths which makes it impossible to undeploy the beans.
Weblogic Conclusion Interview FAQs
We know the list of Weblogic Interview Questions and Answers, Weblogic Interview Questions and Answers Freshers, Weblogic Interview Questions and Answers, Weblogic Interview Questions is overwhelming but the advantages of reading all the questions will maximize your potential and help you crack the interview. The surprising fact is that this Weblogic interview questions and answers post covers all the basic of the Weblogic technology and you have to check out the FAQs of different components of Weblogic too.
However, you will be asked with the questions in the interview related to the above mentioned questions. Preparing and understanding all the concept of Weblogic technology will help you strengthen the other little information around the topic.
After preparing these interview questions, we recommend you to go for a mock interview before facing the real one. You can take the help of your friend or a Weblogic expert to find the loop holes in your skills and knowledge. Moreover, this will also allow you in practicing and improving the communication skill which plays a vital role in getting placed and grabbing high salaries.
Remember, in the interview, the company or the business or you can say the examiner often checks your basic knowledge of the subject. If your basics is covered and strengthened, you can have the job of your dream. The industry experts understand that if the foundation of the student is already made up, it is easy for the company to educate the employ towards advance skills. If there are no basics, there is no meaning of having learnt the subject.
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We hope that you enjoyed reading Weblogic Interview Questions and Answers, Weblogic Interview Questions and Answers Freshers, Weblogic Interview Questions and Answers, Weblogic Interview Questions and all the FAQs associated with the interview. Do not forget to revise all the Weblogic interview questions and answers before going for the Weblogic interview. In addition to this, if you’ve any doubt or query associated with Weblogic, you can contact us anytime. We will be happy to help you out at our earliest convenience. At last, we wish you all the best for your upcoming interview on Weblogic Technology.