First adaptation step 1

Difference in HashMap and you can HashTable? (HashMap allows null opinions because trick and cost whereas Hashtable doesnt allow). HashMap cannot make certain your order of one’s chart tend to are lingering through the years.

Determine version of Organization Kidney beans? Session kidney beans -> Of this a consumer and possess states having a consumer Organization Kidney beans -> Represents some organization into the chronic stores such a databases

What is enterprise bean? ? Machine front reusable coffees role ? Has the benefit of properties that are tough to implement from the programmer ? Sun: Firm Bean architecture is part tissues towards implementation and you will development of component-based distributed company programs. Software created playing with organization coffee beans was scalable, transactional and you will multi-user secure. This type of apps may be authored once after which implemented towards the one host plattform you to definitely supports enterprise coffee kidney beans specification. ? Organization kidney beans are carried out from the J2EE servers.

Entity Beans ? Represents one to line about databases

0 contains tutorial beans, entity kidney beans were not provided. Entity kidney beans have been set in version step 1.step 1 and that appeared throughout 12 months 1999. Most recent discharge try EJB type step 1.dos

Attributes of EJB? Database management –Databases union pooling –DataSource, provided by new J2EE host. Necessary to access connection pond of host. –Database accessibility is actually set up for the J2EE servers -> easy to alter databases / database rider Exchange administration –Marketed purchases –J2EE server even offers deal display which will be accessed by the customer. Safeguards government –Authetication –Authorization –encryption Organization coffees kidney beans is delivered /duplicated on independent servers

lDistribution/duplication also offers –Load controlling, weight will likely be divided into independent machine. –Failover, if an individual servers goes wrong, others will keep towards processing typically. –Performance, you to definitely server isn’t very heavier loaded. Plus, like Weblogic possess bond pools for improving overall performance in one host.

When you should choose EJB? Server would be big stacked –Shipping regarding server helps to achieve best abilities. Host need to have simulation to your matter-of failure of one machine. –Replication is actually hidden towards the designer Marketed deals are expected –J2EE server now offers deal display which takes proper care of exchange government. –Marketed deals is actually undetectable towards programmer ? Other services vs. money Weblogic J2EE host

Have you thought to to utilize 100 % free J2EE host? –zero tecnical assistance –more complicated to utilize (no graphical user interface . ) –no integration in order to development tools (eg, Jbuilder) –Pests? Other difficulties through the investment?

Alternative:Tuxedo ? Tuxedo are a middleware which provides scalability properties and you can transaction inspections. ? C or C++ centered. ? Can be utilized having Java customer by the classes within the JOLT package provided by BEA. Quicker you to J2EE servers?

J2EE machine now offers ? DataSource. –Object that can be used to achieve databases connection on partnership pond. –Are going to be accessed from the program DataSource ? Exchange monitor –Will be accessed by interface UserTransaction. ? Java Naming therefore the List Solution

Coffees Naming and also the List Solution ? Naming provider is needed to to locate beans home interfaces or other objects (DataSource, UserTransaction) –Such as for example, jndi identity of your own DataSource ? List service is needed to shop and you may recover functions by their identity. –jndi term: java:comp/env/propertyName

XML – deployment descriptor ejb-container.xml + server-certain xml- document That’s next Manufactured inside the a jar – file as well as bean groups. Kidney beans was manufactured on the EJB Container file , Reveal document is used to help you number EJB’s and you can jar file holding Implementation descriptor.

Class Bean Creator programs about three categories: –Home software, contains tricks for carrying out (and you can locating to have organization beans) bean circumstances. –Secluded program, consists of providers steps the fresh bean now offers. –Bean classification, provides the providers logic of your own company bean.