Very first type step one

Difference in HashMap and you will HashTable? (HashMap lets null opinions as the key and cost whereas Hashtable doesnt allow). HashMap cannot make sure the transaction of your own chart have a tendency to remain ongoing throughout the years.

Identify version of Company Beans? Lesson kidney beans -> Regarding the a customer and you can has says to have a consumer Organization Beans -> Means certain organization inside chronic sites such as for instance a databases

What exactly is company bean? ? Servers top reusable java part ? Offers attributes that are difficult to implement by the programmer ? Sun: Enterprise Bean buildings is part structures to the deployment and growth of parts-created distributed organization applications. Software composed using agency coffee kidney beans is scalable, transactional and you may multiple-member safe. Such programs can be authored once immediately after which implemented to your one server plattform you to definitely helps corporation java kidney beans requirements. ? Enterprise kidney beans are executed by the J2EE host.

Organization Beans ? Is short for one line regarding databases

0 contained course kidney beans, organization beans weren’t included. Entity beans had been placed into version step 1.step 1 which appeared through the year 1999. Current release is actually EJB adaptation step one.dos

Attributes out of EJB? Databases administration –Databases union pooling –DataSource, provided by the J2EE server. Had a need to availableness relationship pool of your own host. –Databases accessibility is actually set up with the J2EE servers -> easy to changes database / databases driver Exchange management –Delivered transactions –J2EE machine also provides purchase display screen which is accessed from the visitors. Coverage administration –Authetication –Consent –security Corporation coffee beans will likely be marketed /duplicated with the independent hosts

lDistribution/replication now offers –Stream balancing, weight will likely be put into separate machine. –Failover, if an individual machine goes wrong, others will keep for the control typically. –Results, you to definitely server is not very big piled. As well as, for example Weblogic possess bond pools to own improving show in one single host.

When you should favor EJB? Servers would be hefty loaded –Delivery away from server really helps to achieve most useful performance. Servers need replica towards the matter of inability of a single server. –Duplication is invisible on the programmer Marketed purchases are needed –J2EE server even offers purchase display screen which takes care of deal government. –Marketed deals try invisible to your programmer ? Almost every other services compared to. currency Weblogic J2EE machine

You will want to to utilize totally free J2EE servers? –zero tecnical service –more challenging to make use of (zero graphical user interface . ) –zero integration to help you advancement products (eg, Jbuilder) –Insects? Other difficulties through the enterprise?

Alternative:Tuxedo ? Tuxedo try a beneficial middleware which provides scalability attributes and you will exchange monitors. ? C otherwise C++ mainly based. ? May be used with Coffees customer by kinds within the JOLT bundle offered by BEA. Shorter one to J2EE server?

J2EE servers now offers ? DataSource. –Target used to achieve database partnership about partnership pond. –Would be utilized by interface DataSource ? Purchase monitor –Should be reached of the interface UserTransaction. ? Java Naming therefore the Index Service

Coffees Naming and Directory Solution ? Naming service is needed to to find beans domestic interfaces and other items (DataSource, UserTransaction) –Such as, jndi name of DataSource ? Directory service must store and you will access features from the their name. –jndi name: java:comp/env/propertyName

XML – implementation descriptor ejb-jar.xml + server-specific xml- file Which is following Packaged in a container – document along with bean kinds. Kidney beans is manufactured to your EJB Jar file , Manifest file is employed so you’re able to record EJB’s and you can container document carrying Implementation descriptor.

Class Bean Designer apps about three classes: –Household program, include tricks for carrying out (and you may discovering to have entity beans) bean period. –Secluded software, includes business procedures the fresh new bean also offers. –Bean category, has the team logic of company bean.