Java review-basic6

1. Weak References:

In computer programming, a weak reference are a reference that does isn't protect the referenced object from collection by a Garbage collector, unlike a strong reference. An object referenced-weak references–meaning "every chain of references that reaches the object includes at LEAs T one weak reference as a link "–is considered weakly reachable, and can be treated as unreachable and so may collecte D at any time. Some garbage-collected languages feature or support various levels of weak references

Personal Understanding:

Weak reference cannot protect itself from being recycled like a strong reference, so it can be recycled at any time like the unreachable type.

2.JINI

Jini (pronounced djee-nee like the Arabic word for "magician") was a network architecture concept that Sun Microsystems cal LS "Spontaneous networking." Using Jini, users would be able to plug printers, storage devices, speakers, and any kind of device directly into a net work and every other computer, device, and user on the network would know that the new device have been added and is AV Ailable. Each pluggable device would define itself immediately to a network device registry. When someone wants to use or access the resource, their computer would be able to download the necessary programming from I T to communicate with it. No longer would the special device support software known as Adevice driver need to being present in an operating system. The operating system would know about all accessible devices through the network registry.

Personal Understanding:

Jini is a system that can be added to other devices as long as he has device registry

3.

Jms:it is a messaging standard this allows application components based on the Java Enterprise Edition (Java EE) to creat E, send, receive, and read messages. It allows the communication between different components of a distributed application to be loosely coupled, reliable, and Asynchronous.

JMS Provider:an Implementation of the JMS interface for a Message oriented middleware (MOM). Providers is implemented as either a Java JMS implementation or an adapter to a Non-java MOM.

JMS Client:an application or process that produces and/or receives messages.

JMS producer/publisher:a JMS client that creates and sends messages.

JMS consumer/subscriber:a JMS client that receives messages.

JMS Message:an object that contains the data being transferred between JMS clients.

JMS queue:a Staging Area This contains messages that has been sent and is waiting to is read (by only one consumer). Contrary to the name of the queue suggests, messages don ' t has to be received in the order in which they were.

A JMS Queue:only guarantees that each message is processed only once.

JMS topic:a distribution mechanism for publishing messages, that is delivered to multiple subscribers.

Personal Understanding:

It ' s a messaging system and Java component can create, send, recive and read Message form This system, we can send string Type or Serlized object.

3.JGroups:

JGroups is a reliable multicast system written in the Java language.

JGroups adds a "grouping" layer over a transport protocol, internally keeping a list of participants. This list was used to:

make the application aware of the listeners

make some or all transmissions reliable

allow totally ordered transmissions

JGroups is a toolkit for reliable multicast communication. It can used to the create groups of processes whose members can send messages to each of the other. JGroups enables developers to create reliable multipoint (multicast) applications where reliability is a deployment issue. JGroups also relieves the application developer from implementing this logic themselves. This saves significant development time and allows for the application to being deployed in different environments without ha Ving Tsun to change code.

Personal Understanding:

It's a layer add over transport protocol in order OT multicast communication.

Java review-basic6