Drop Down MenusCSS Drop Down MenuPure CSS Dropdown Menu

Tuesday, June 11, 2019

Weblogic job interview questions and answers:

What is Weblogic?

WebLogic is 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.

What is the basic components of Weblogic Server?

Basic weblogic components as follows:
1)Domains
2)Admin Server
3) Managed Server
4) Node Manager
5) Weblogic Server Cluster

What is the Domain in Weblogic Server?

What is the Server?

What is the Admin Server?

What is the Managed Server?

How Admin Server And Managed Servers  Interacts?

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.

What is the Msi Mode in Weblogic? How can You Enable And Disable this Option?

MSI is 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 as below:
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

Difference between Weblogic Development and Production Mode?

Development 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
Production Mode:
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

How to change to Production Mode from Development Mode  In Weblogic 10.3?

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.
1. 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.
set PRODUCTION_MODE=false
2. Save your changes and exit the text editor.

What Is Boot.proerties File In Weblogic Server?

boot.properties is the file used by admin or managed server during startup for username and password. It exist under  domain_home/servers/server_name/security dir.

What are Installation modes for Weblogic Server?

There are 3 types of weblogic installation.
1)Graphical mode
2)console mode
3)silent mode

What Is Config.xml?

It is the central configuration repository for a domain.it contains the configuration of the domain like entries of the servers, clusters, data-sources etc. It is under domain/config.

How do we provide User Credentials while Starting Weblogic Server?

When creating a domain, the Configuration Wizard prompts to provide the username and password for an initial administrative user. If domain created 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.

Can we start a Managed Server if  Administration Server is not available?


What is a Weblogic Server Cluster?


Group of WebLogic Managed Server Instances that work together to provide high availability and scalability for applications is called cluster. WebLogic Servers with in cluster can run on same machine or different machines. These are also called as managed Server cluster.All the servers in a cluster must be in same domain. All servers in a cluster must be same version level, though they can run on different machines.

Advantage Of Clustering?

WebLogic clustering offers following important benefits:
Scalability :  The capacity of an application deployed on a WebLogic Server cluster can be increased dynamically to meet demand. You can add server instances to a cluster without interruption of service — the application continues to run without impact to clients and end users.
Load balancing : The ability to distribute requests across all members of the cluster, according tothe workload on each server.
High availability : A mix of features that ensure applications and services are available even if aserver or machine fails.Clients can continue to work with little or no disruption ina highly available environment. WebLogic achieves high availability using acombination of features: replication, failover, and migratable services.

Difference between Multicast And Unicast in Weblogic?

Multicast : Multicast is easier to explain over Unicast. Multicast is a broadcast UDP option for sending a packet/announcement over to a group that is listening on a specific multicast address and port over which the announcement is sent.There is a defined range for valid Multicast address (224.0.0.1 to 239.255.255.255). Everyone listening on the given address hears the announcement just like following a Twitter post. Some limitations with Multicast is the TTL (time to live) across machines/subnets/routers needs to be adjusted and the routers configured to retransmit the multicast packet across subnets.

Multicast: It is a kind of clustering system where there is no cluster master and each and every server needs to ping each other for informing their existence. Multicasting has many messages to be sent in the form of ping as each server needs to inform all others about its existence. This condition creates much complexity associated with the method compared to unicast.

Unicast : Unicast is more of a point to point UDP option to send the packet to a specific member and not everyone. That way, unicast is more of a private conversation between two individuals while multicast is more of a shout to a group or room. Both are UDP based, so there can be losses unlike TCP that handles retransmissions on message loss. But Unicast can span across routers and does not have to worry about TTL without the everyone hearing the announcement. So, Network Admins in general prefer to go with Unicast over Multicast for these reasons.

Unicast is the method used in the clustering technique where there are cluster master and each server should ping to this cluster master for informing that the server is alive.











No comments:

Post a Comment