111.What is a Connection Pool?
- A connection pool is a group of ready-to-use database connections associated with a data source.
- Connection pools:
- Are created at Oracle WebLogic Server startup
- Can be administered using the Administration Console
- Can be dynamically resized to accommodate increasing load
112.What are the benefits of having Data Sources and Connection Pools in Weblogic?
- The following are some advantages of this approach:
- Time and overhead are saved by using an existing database connection.
- Connection information is managed in one location in the Administration Console.
- The number of connections to a database can be controlled.
- The DBMS can be changed without the application developer having to modify the underlying code.
- A connection pool allows an application to “borrow” a DBMS connection
113.How Data Sources are used in Weblogic?
A client retrieves a data source through a JNDI lookup and uses it to obtain a database connection.
114.What is Multi Data Sources?
- Multi data source:
- Is an abstraction around a group of data sources
- Determines which data source to use to satisfy the request depending on the algorithm selected in the multi data source configuration:
- Load balancing or failover
- Is bound to the JNDI tree
- XA support for multi data sources:
- The WLS JDBC supports using multi data sources in XA transactions.
- You can configure the data sources contained within the multi data source to use XA JDBC drivers.
115.What is the functionality of “Message-Oriented Middleware”?
- Message-oriented middleware refers to an infrastructure that supports messaging.
- Typical message-oriented middleware architectures define the following elements:
- Message structure
- The way to send and receive messages
- Scaling guidelines
116.Explain about Point-to-Point (Queue)?
Many producers can serialize messages to multiple receivers in a queue.
117.Explain about Publish-Subscribe (Topics)?
Publishing and subscribing to a topic decouples producers from consumers.
118.Explain about Oracle WebLogic Server JMS Features?
Oracle WebLogic Server JMS supports:
- PTP and pub/sub domains
- Guaranteed and transactional message delivery
- Durable subscribers
- Distributed destinations
- Recovery from failed servers
119.How will you implement “Messaging Service” in Weblogic?
- In Oracle Weblogic Server, the messaging service is implemented through a JMS server.
- A JMS server receives and distributes messages.
120.What is the user of “Connection Factories” in JMS?
- JMS connection factories are used to set default client connection parameters, including:
- Message priority
- Message time-to-live (TTL)
- Message persistence
- Transactional behavior
- Acknowledgement policy
- Flow control
- WLS provides a default client connection factory that:
- Uses WebLogic’s default connection settings
- Is located on the server JNDI tree at weblogic.jms.ConnectoryFactory