Weblogic Interview Questions And Answers Pdf
1.What is Weblogic?
Answer: WebLogic may be a J2EE application server and also an HTTP web server by Oracle, for Unix, Linux, Microsoft Windows, and other platforms. WebLogic supports Oracle, DB2, Microsoft SQL Server, and other JDBC-compliant databases.
2. what’s SSL in WebLogic?
Answer: Secure Sockets Layer (SSL) whch provides the secure connections by allowing two applications
which are connecting by the network connection to authenticate the other’s identity and by encrypting the info
exchanged between the applications. Authentication allows a server and by choice one of the client to verify the
identity of the appliance on the opposite end of a network connection. Encryption makes data transmitted
over the network intelligible only to the intended recipient
3. what percentage ways to start out and stop WebLogic servers?
Answer: There are some ways to start out & stop WebLogic Admin and managed servers:
You can be able to start and stop Admin Server by :
1) Script
2) “Java Weblogic.server “command(The WebLogic.Server class is that the main class for a WebLogic Server
instance)
3) From startup option on windows
4) WLST with or without node manager
You can start managed servers using:
1) scripts
2) admin console
3) using WLST
4) using node manager
5) java WebLogic.server command( The WebLogic.Server class is that the main class for a WebLogic
Server instance )
4. How can you differentiate between T3 and HTTP protocol?
Answer: The WebLogic randomly use T3 protocols for internal and external connections to the servers. The T3 protocol often is employed in WebLogic implementation of RMI. Proprietary of WebLogic Server.
Http protocols are used primarily for HTTP communication between the browser and therefore the webserver. Standard follows the W3C (World Wide Web Consortium).
Note: All of those protocols are, by default, multiplexed over an equivalent connection to the server’s address and port. So you’ll access an internet page hosted by the server employing a URL like An external client can found out an initial JNDI context to a server using the URL t3://host: port/. All that has changed is that the protocol over which the client must communicate with the server.
5. What are the different States of the Weblogic Server?
Answer: There are 9 states of the server and they have been listed below.
Shutdown
Starting
Standby
Resuming
Running
Suspending
Shutting down
Failed
6. How both Administration Server And Managed Servers Will Interact with each other?
Answer: The Administration Server stores the master of the domain configuration, including the configuration for all Managed Servers within the domain. Each Managed Server stores an area copy of the domain configuration file. When a Managed Server gets started, it connects to the Administration Server to synchronize the configuration. After all When all the Modifications are done , the Administration Server sends the changed configuration to the Managed Servers.
7. what’s Boot?properties enter Weblogic Server?
Answer: boot.properties is that the file employed by admin or managed server during startup for username and password. it exist under your domain/servers/server_name/security folder.
8. what’s Config.xml?
Answer: config.xml is that the central configuration repository for a website . The Every supplies you have got will be configured from the admin console or by instruction or by the other tool registered under this file.WLS 9.x onwards, this file contains references to other xml configuration files also those are under your domain/config folder ( further subfolder thereunder for respective resources ).
9. what’s Multicast And Unicast In Weblogic?
Answer: Multicast: Multicast is simpler to elucidate over Unicast. Multicast may be a broadcast UDP option for sending a packet/announcement over to a gaggle that’s listening on a selected multicast address and port over which the announcement is shipped . there’s an outlined range for valid Multicast address (224.0.0.1 to 239.255.255.255). Everyone listening on the given address hears the announcement a bit like following a Twitter post. Some limitations with Multicast is that the TTL (time to live) across machines/subnets/routers must be adjusted and therefore the routers configured to retransmit the multicast packet across subnets
Unicast: Unicast is more of some extent to point UDP choice to send the packet to a selected member and not everyone. That way, unicast is more of a personal conversation between two individuals while multicast is more of a shout to a gaggle or room. Both are UDP based, so there are often losses, unlike TCP that handles retransmissions on message loss. But Unicast can reach over routers and they doesn’t need to worry about TTL . So, Network Admins, generally , like better to accompany Unicast over Multicast for these reasons.
10. Explain me the different Methods For Providing User Credentials For Starting The Server?
Answer: At the time of the creation of domain, the wizard for setting configuration asks for the small print like user name, password, etc. from the user who is logging certain the primary time as an administrator. If the domain is made in development mode, the configuration wizard saves the encrypted password also because the username inside an identity file. This file is out there for reference during the time of booting in order that within the absence of this file, the system can prompt the user for the aim of entering credentials. a replacement boot – identity file are often created if you would like to vary the user credentials alternatively if you’re having the need of making a website within the production model.
11. what’s the simplest thanks to set the classpath?
Answer: WebLogic Server installs the subsequent script that you simply can use to line the classpath that a server requires:
WL_HOMEserverbinsetWLSEnv.cmd (on Windows)
WL_HOME/server/bin/setWLSEnv.sh (on UNIX).
12. what percentage types does one configure managed server in WebLogic server?
Answer:
Three types
1)Domain Configuration Wizard
2)Administration Console
3)Weblogic Scripting Tool
13. How does one set the classpath?
Answer: WebLogic Server installs the subsequent script that you simply can use to line the
classpath that a server requires:
WL_HOMEserverbinsetWLSEnv.cmd (on Windows)
WL_HOME/server/bin/setWLSEnv.sh (on UNIX)
14. How does a server will be knowing when another server is unavailable?
Answer: WebLogic Server uses two mechanisms to work out if a given server instance is unavailable. Each
WebLogic Server instance during a cluster uses multicast to broadcast regular “heartbeat” messages that
advertise its availability. By monitoring heartbeat messages, server instances during a cluster determine when
a server instance has failed. If they do not receive three following heartbeats from one end of the server the opposite server instances will drop a server instance from the cluster .
WebLogic Server also monitors socket errors to work out the supply of a server instance. For
example, if server instance A has an open socket to server instance B, and therefore the socket unexpectedly closes,
server A assumes that server B is offline
15. How Can Port Number Be Checked?
Answer: Port number are often checked by using netstat-na|grep connected.
16. What Are the varied sorts of Weblogic Installations?
Answer:
The WebLogic installation Consists usually occurs in three different modes which are:
Graphical mode
Console mode
Silent mode.
17. Explain The Term Clustering?
Answer: Clustering means grouping which servers together for accomplishing high percentage of scalability and availability.
18. what’s the aim Of Clustering?
Answer: The main goal of performing the method of clustering is to form high scalability also because the availability of the servers possible. This process also helps in balancing the load during a proper manner and also accomplishes failover.
19. How Can Cluster Communication Occur?
Answer: The communication through cluster is formed possible by the multicast IP also as a port by the method of sending periodic messages which are normally called as heartbeat messages.
20. we frequently see BSU when using WebLogic. what’s the meaning of BSU?
Answer: Oracle bought Weblogic from BEA. BSU Stands for Bea Smart Update. This utility is employed to use the WebLogic Server Patches. In simple terms, it’s the primary letter of the name of founders Bill Coleman, Ed Scott, and Alfred Chuang.
21. Do we have any Possibility to Start a Managed Server During Absence Of Administrator Server?
Answer: The standard process is that just in case of any difficulty for the management server to urge connected to any administration server at the time of start-up, there’s an option for the managed server to retrieve the configuration associated with it from the configuration files also as other files involved. the knowledge thus retrieved can’t be altered and it’s possible only the administration server is basically available. When the administration server is unavailable, then the managed server enters into its independence mode for completing its operations.
22. What are the different modes of operation for Weblogic server domains?
Answer:
There are two modes
Development mode:
You use development mode while you’re developing your applications. In the Development form of mode it generally uses a relaxed security configuration and which enables you to auto-deploy applications.
Production mode:
You can use production mode while the application is running in the final form. A production domain uses full security and should use clusters or other advanced features.
23. what’s Horizontal and vertical clustering?
Answer: There are two methods .
Horizontal clustering: Basically it involves running multiple Java application servers that run on two or more
separate physical machines.
Horizontal scaling is more reliable than vertical scaling since there are multiple machines involved within the
cluster environment, as compared to just one machine
Vertical clustering: However, consists of different kinds of Java application servers on one physical machine.
With vertical scaling the machine’s handle power, usage of Central processing Unit , and JVM heap memory configurations are the most factors choose what percentage server instances should be run on one machine.
24. what’s the essential Components of Weblogic Server?
Answer: These are the essential WebLogic components
1)Domains
2)Admin Server
3) Managed Server
4) Node Manager
5) Weblogic Server Cluster
25. What are stating modes which are available in the Weblogic Server?
Answer:
There are three starting modes are available:
1) Stage mode: Administration Server directly copies the files from their original location on the
Administration Server machine to the staging directories of each and every server which is targeted .
2) External Stage: The targetted servers place using local copies of the deployment files, here the
Administration Server does not automatically copy the files to targeted servers in
external_stage mode; instead, you want to copy the files to the staging directory of every target server before
deployment.
3) No Stage: In This stage the Administration Server do not copy deployment unit files; instead, all servers deploy
using an equivalent physical copy of the deployment files, which must be directly accessible by the
Administration Server and target servers
26. what’s a Thread dump? How will you’re taking in Unix/Linux and windows?
Answer:
A Java thread dump may be a way of checking out what every thread within the JVM is doing at a specific
point in time this is useful . If Java application sometimes seems to hold ( or )running a little bit slower when running with load, as an analysis of the dump will show where the threads are stuck.
1) Linux : kill -3 2) Windows (console mode): crtl+break
3) Windows (service): basic -dump -svc name:mydomain_myserver
27. What are the modes which support installation for WebLogic Server?
Answer:
Graphical mode, console mode, and silent mode.
28. what’s the function of T3 in WebLogic Server?
Answer:
It gives enhancements support for WebLogic Server messages which is provided by T3. These enhancements include replacement of object , which the work is done in WebLogic Server clusters’ context and HTTP. Java Object Serialization, RMI predation is completed by T3. T3 may be a superset of java Object. Serialization and RMI are often done over T3.
Between WebLogic Servers, and between programmatic clients & a WebLogic Server cluster, T3 is remitted . to speak between processes and WebLogic Server, the protocols HTTP and IIOP are often used and optional.
The HTTP is employed to speak between a browser and a WebLogic Server. The IIOP is employed to speak between an Object Request Broker and weblogic server
29. How do stubs add a WebLogic Server cluster?
Answer: The support is provided by T3. These factors include replacement of a object, which works in an WebLogic Server clusters’ context and HTTP. Java Object Serialization, RMI predation is completed by T3. T3 may be a superset of java Object. Serialization and RMI are often done over T3.
Between WebLogic Servers, and between programmatic clients & a WebLogic Server cluster, T3 is remitted . to speak between processes and WebLogic Server, the protocols HTTP and IIOP are often used and optional. The HTTP is employed to speak between a browser and a WebLogic Server. The IIOP is employed to speak between an Object Request Broker and WebLogic Server.
30. How we are Supposed to start the Managed Server If The Administration Server Is Not available?
Answer: By default, if a Managed Server is unable to attach to the required Administration Server during startup, it can retrieve its configuration by reading a configuration file and other files directly. you can’t change the server’s configuration until the Administration Server is out there . A Managed Server that starts during this way is running in Managed Server Independence mode.
31. what’s A Weblogic Server Cluster?
Answer: It consists of multiple WebLogic Server which running simultaneously and also dealing combinely to supply increased scalability and reliability.
A cluster appears to clients to be one WebLogic Server instance. The server which consists of a cluster which can run on an equivalent machine, or be located on different machines.
Cluster’s capacity can be increased by addition of some server instances to the cluster on an existing machine, otherwise you can add machines to the cluster to host the incremental server instances.
Each server instance during a cluster must run an equivalent version of WebLogic Server.
32. Explain about WebSphere MQ Real-time transport?
Answer:
WebSphere MQ Real-time Transport may be a lightweight protocol optimized to be used with nonpersistent messaging.
It is employed by JMS clients and provides high levels of scalability and message throughput.
WebSphere MQ Real-time Transport is right for applications where large numbers of messages got to be sent or where messages got to be sent to large numbers of client applications.
The WebSphere MQ Real-time Transport doesn’t provide any facilities for persistent messaging or durable subscriptions.
33. Explain the concepts and capabilities of ANT?
Answer: Open: Ant comes under a open source project available in the Apache license. Therefore, its ASCII text file are often downloaded and modified. Also Ant utilize XML build files which is making the development very easy.
Cross-Platform: Use of XML along side Java makes Ant the right solution for developing programs designed to run or be built across a variety of various operating systems.
Extensible: The very Newly added tasks gets extend with the capabilities, while build listeners are wont to helping hook into the build process to feature extra error tracking functionality.
Integration: As Ant is extensible and open, it are often integrated with any editor or development environment easily.
34. what’s C-HTML?
Answer: Compact-HTML (a subdivsion of HTML for less information providing devices) which was created by Japan-based Access Company and was accepted by the W3CM in 1998.
Some of the Devices cellular phones have several hardware restrictions like small memory, low power CPUs, small mono-color display screens and restricted input methods.
CHTML doesn’t support JPEG images, tables, image maps, multiple fonts and designs of fonts, background colors and pictures , frames, style sheets and quite two colors, typically black and white.
The basic operations are often done by a mixture of 4 buttons:
cursor forward
cursor backward
select
back/stop
35. what’s the difference within the web.xml and weblogic.xml?
Answer: One of the application-specific XML-which is based for deployment descriptor file named web.xml, which is listed in your application’s J2EE components and their configurations as J2EE modules. Each J2EE module may be a collection of 1 or more J2EE components of an equivalent container type (Web or EJB) that are represented by one component deployment descriptor for that type within the web.xml file.
A file named weblogic.xml, in which it defines how named resources within the web.xml file are mapped to WebLogic Server resources ( File – WebLogic-specific formation descriptor ). The samples of weblogic.xml include HTTP session parameters, HTTP cookie parameters, JSP parameters, resource references, security role assignments, and container attributes.
36. How can we change from default JVM to others?
Answer: once you upgrade a website to WebLogic Server 8.1, consider upgrading your JVM to JRockit. WebLogic JRockit may be a JVM designed for running server-side applications in Windows and Linux running on Intel architectures. For the server-side applications, JRockit has some advantages other than virtual machines:
It employs adaptive optimization, which detects and removes bottlenecks within the deployed application.
It is designed specifically for the special requirements of server-side applications, which tend to be parallel and thread-intensive, to run longer periods of your time , and to not use graphical interfaces.
You can easily observe JRockit by using WebLogic Server Administration Console.
Steps to change:
You can set server start scripts to set JAVA_HOME for instance , change:
@rem Set user-defined variables.
set JAVA_HOME=WL_HOMEjdk131
where WL_HOME is that the WebLogic Server 7.0 installation directory, to
@rem Set user-defined variables.
set JAVA_HOME=WL_HOMEjrockit81_141_02
where WL_HOME is that the WebLogic Server 8.1 installation directory.
so Change domain’s config.xml to use the JRockit javac.exe. for instance , change
JavaCompiler=”WL_HOMEjdk131binjavac”
where WL_HOME is that the WebLogic Server 7.0 installation directory, to
JavaCompiler=WL_HOMEjrockit81_141_02binjavac”
where WL_HOME is that the WebLogic Server 8.1 installation directory. Remove any switches specific to the Sun JVM from server start scripts for instance , from the beginning command:
echo on “%JAVA_HOME%binjava” -hotspot …. WebLogic.Server delete “-hotspot”
37. How to make a managed server?
Answer: v Backup the configuration by changing the config.xml with config.xml_date
v Configure the changes within the start managedWebLogic.sh /cmd with WebLogic home and java home and provides the admin servers URL updated
v attend WebLogic admins console and add a managed server and provides the IP and port of the managed server. all the changes confirmed then start the server using start managedWebLogic.sh script present within the domain bin.
38. what’s a license file?
Answer: Now you would like to register with Oracle Support ID to urge updated license xml file.
39. the way to configure a DB connection pool?
Answer:
Choose the DB type (Oracle, Sybase, Mysql, etc…)
Then choose the driving force type for the DB.
Give the connection pool name.
Provide the name, DB Service ID, schema and also password.
Then it’ll invite testing the connection pool/DataSource.
After a successful connection, it’ll ask you to make and deploy the connection pool target to server or cluster. After creating a replacement connection pool always point the JDBC store to the connection pool created. this is often required because A JMS JDBC store are going to be used for persistent messaging.
After each and every JDBC connection, we have to once again start ( re-start ) the server if there startup classes exists , otherwise no restart required in WebLogic 9.x and better versions.
40. what’s JNDI?
Answer: Java Naming and Directory Interface
Applications use naming services to locate objects data sources, EJBs, JMS, MailSessions, then on within the WebLogic domain. A naming service associates names with objects and finds objects t3 protocol are going to be used. (The RMI registry may be a exemplar of a naming service.)
JNDI provides a common-denominator interface to several existing naming services, like LDAP (Lightweight Directory Access Protocol) and DNS (Domain Name System). These naming services maintain a group of bindings, which relate names to things and supply the power to seem up objects by name. JNDI allows the components in distributed applications to locate one another .
The implementation of JNDI supplies some methods :
To the WebLogic Server naming services provide clients access
Make objects available within the WebLogic namespace
Retrieve objects from the WebLogic namespace
41. what’s The Advantage Of Clustering?
Answer:
WebLogic clustering offers three important benefits:
1. Scalability: The capacity of an application has been implemented on WebLogic Server cluster are increased dynamically to satisfy the demand. you’ll add server instances to a cluster without interruption of service — the appliance continues to run without impact to clients and end-users.
2. Load balancing: the power to distribute requests across all members of the cluster, consistent with the workload on each server.
3. High availability: a mixture of features that ensure applications and services are available albeit a server or machine fails. Clients can still work with little or no disruption ina highly available environment.
42. what’s extended deployment in WebSphere?
Answer:
It delivers strengthen Qualities of Service with features for optimizing IT resources.
The suite comprises of three products:
WebSphere Virtual Enterprise:
It increases flexibility and agility which make sure of business process integrity, application performance, and better manage health, improving services.
It provides some capabilities which lowers the costs required to make , manage and run enterprise applications and an SOA environment.
WebSphere eXtreme Scale:
It is an important IBM software technology for conducting extreme transaction processing.
It permits applications to large volumes of transactions with extreme efficiency and linear scalability.
It provides transactional integrity and transparent failover to make sure high availability, high reliability, and constant response times.
It can be operated an in-memory data grid which lively caches, splitting, reproduce and manages application data and business logic across multiple servers.
Compute Grid:
It also enables the organize and track of batch type jobs with enhanced service policy and workload management.
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