First version step one

Difference between HashMap and HashTable? (HashMap allows null philosophy since key and value whereas Hashtable doesnt allow). HashMap does not make certain that the order of one’s chart commonly continue to be ongoing throughout the years.

Define type of Company Kidney beans? Course kidney beans -> In the a customer and you will possess states to own a customer Entity Beans -> Stands for certain organization into the chronic stores like a databases

What’s agency bean? ? Machine front reusable coffees parts ? Offers features that are difficult to incorporate by the programmer ? Sun: Corporation Bean frameworks is part architecture to your implementation and you will growth of parts-dependent marketed company apps. Applications authored having fun with organization coffees kidney beans try scalable, transactional and you will multi-member secure. This type of applications is created just after then implemented on the people server plattform you to aids enterprise coffee kidney beans specs. ? Company beans are carried out from the J2EE machine.

Organization Kidney beans ? Is short for you to definitely line regarding database

0 consisted of session kidney beans, entity kidney beans were not integrated. Entity beans was in fact put in variation step one.step 1 and that showed up throughout the year 1999. Newest discharge was EJB version step 1.dos

Characteristics off EJB? Databases government –Database connection pooling –DataSource, provided by the J2EE machine. Wanted to supply partnership pond of your own server. –Database access are designed towards J2EE machine -> an easy task to change database / databases driver Transaction administration –Delivered transactions –J2EE host offers deal display screen which will be accessed of the visitors. Safety government –Authetication –Agreement –security Agency coffee beans can be marketed /replicated toward separate machines

lDistribution/duplication now offers –Stream controlling, stream are going to be split up into separate machine. –Failover, if one server fails, someone else could well keep into running generally. –Show, you to host isn’t so hefty loaded. And additionally, such as for instance Weblogic has actually thread pools to possess boosting overall performance in one servers.

When to choose EJB? Machine could well be heavy piled –Distribution out of server really helps to get to most useful efficiency. Host must have replica towards question of failure of one servers. –Duplication was undetectable towards the programmer Marketed transactions are required –J2EE server now offers purchase display which will take proper care of transaction management. –Distributed deals are undetectable on the programmer ? Most other services versus. currency Weblogic J2EE machine

Then to utilize 100 % free J2EE server? –zero tecnical support –much harder to use (zero graphical user interface . ) –zero combination so you’re able to invention products (such as for example, Jbuilder) –Insects? Other difficulties throughout the enterprise?

Alternative:Tuxedo ? Tuxedo are a middleware that gives scalability functions and you may exchange checks. ? C otherwise C++ based. ? Can be utilized which have Coffees buyer of the classes into the JOLT package given by BEA. Faster one to J2EE servers?

J2EE host offers ? DataSource. –Target used to reach databases union throughout the connection pond. –Shall be utilized of the screen DataSource ? Exchange screen –Is reached by screen UserTransaction. ? Coffee Naming and the Index Service

Coffees Naming and also the Index Provider ? Naming provider is needed to discover beans house connects or other items (DataSource, UserTransaction) –Such as for instance, jndi label of your own DataSource ? Index provider must shop and you may retrieve features of the its title. –jndi identity: java:comp/env/propertyName

XML – deployment descriptor ejb-jar.xml + server-specific xml- document Which is then Packaged in a container – document plus bean categories. Beans try packed on the EJB Jar file , Reveal document is utilized to checklist EJB’s and you may jar file carrying Deployment descriptor.

Example Bean Creator apps about three classes: –Household interface, contains tips for doing (and locating to have entity kidney beans) bean era. –Remote program, consists of business steps the bean also offers. –Bean group, gets the business logic of one’s firm bean.