Basic variation step 1

Difference in HashMap and you will HashTable? (HashMap allows null philosophy just like the secret and value whereas Hashtable doesnt allow). HashMap doesn’t ensure that the transaction of one’s chart often continue to be lingering over time.

Describe style of Business Beans? Lesson beans -> With the a client and you can have states getting a customer Organization Beans -> Is short for some organization when you look at the persistent sites including a databases

What’s agency bean? ? Machine front side recyclable coffee part ? Even offers functions which might be tough to implement because of the designer ? Sun: Agency Bean structures is a component architecture for the deployment and you will development of role-dependent distributed team software. Software composed playing with corporation coffees kidney beans was scalable, transactional and you can multiple-representative safe. Such programs can be composed after right more helpful hints after which deployed to the people machine plattform you to supporting company java kidney beans specification. ? Company beans are executed because of the J2EE machine.

Entity Beans ? Stands for you to line about database

0 consisted of class kidney beans, organization kidney beans weren’t incorporated. Entity beans was basically placed into variation step 1.step 1 and therefore made an appearance during 12 months 1999. Current launch is EJB adaptation step one.2

Properties from EJB? Databases government –Databases commitment pooling –DataSource, given by the brand new J2EE servers. Needed to supply union pool of the servers. –Database supply try configured with the J2EE machine -> very easy to alter database / databases driver Transaction government –Distributed transactions –J2EE server even offers purchase screen and that’s reached by consumer. Coverage administration –Authetication –Authorization –encoding Organization coffees beans should be delivered /replicated into the separate hosts

lDistribution/replication also provides –Load balancing, load should be split up into independent servers. –Failover, if an individual servers goes wrong, others could well keep to the operating typically. –Show, one to host isn’t very heavier piled. Also, for example Weblogic features thread swimming pools getting boosting overall performance in one host.

When you should like EJB? Machine would-be hefty piled –Distribution out of servers helps you to achieve ideal abilities. Server need simulation on the question of incapacity of 1 host. –Replication try hidden to your designer Delivered transactions are expected –J2EE servers offers deal display which takes care of purchase administration. –Marketed transactions is invisible on the designer ? Other features compared to. currency Weblogic J2EE host

You need to to make use of 100 % free J2EE server? –no tecnical support –much harder to make use of (no user interface . ) –zero combination in order to invention products (eg, Jbuilder) –Bugs? Other difficulties throughout investment?

Alternative:Tuxedo ? Tuxedo try good middleware that gives scalability attributes and you will exchange checks. ? C or C++ dependent. ? Can be utilized which have Coffees client because of the groups within the JOLT package provided by BEA. Shorter one J2EE machine?

J2EE servers now offers ? DataSource. –Object which can be used to achieve database union about union pool. –Will likely be reached by the program DataSource ? Transaction monitor –Is going to be utilized from the program UserTransaction. ? Coffees Naming plus the Index Provider

Coffees Naming while the Index Solution ? Naming service must to track down kidney beans household connects and other objects (DataSource, UserTransaction) –Particularly, jndi identity of DataSource ? List services is required to shop and you can recover functions by the their name. –jndi term: java:comp/env/propertyName

XML – implementation descriptor ejb-jar.xml + server-particular xml- document Which is up coming Packaged during the a jar – document and bean kinds. Kidney beans was packed on the EJB Container file , Reveal file is utilized to help you record EJB’s and you can jar file holding Deployment descriptor.

Class Bean Creator applications around three classes: –Domestic screen, contains methods for performing (and finding having entity beans) bean hours. –Secluded software, consists of team strategies the brand new bean even offers. –Bean classification, provides the company reason of one’s organization bean.