Brand new HashMap group is approximately equal to Hashtable, except that it’s unsynchronized and you will permits nulls

Brand new HashMap group is approximately equal to Hashtable, except that it’s unsynchronized and you will permits nulls

Basic adaptation step one

Difference in HashMap and you can HashTable? (HashMap lets null opinions while the trick and value while Hashtable does not allow). HashMap will not make certain the transaction of your own chart tend to are ongoing over the years.

Identify sorts of Business Beans? Course beans -> Associated with the a client and have says having a customer Organization Kidney beans -> Is short for specific organization when you look at the persistent stores such a databases

What exactly is agency bean? ? Host front reusable coffees parts ? Even offers functions that will be difficult to apply from the programmer ? Sun: Business Bean structures is a component tissues with the deployment and you will growth of role-depending delivered providers applications. Software written using business coffees kidney beans was scalable, transactional and you may multiple-representative safer. Such software can be composed immediately following right after which implemented towards the one server plattform one to helps corporation java kidney beans specification. ? Firm beans are carried out of the J2EE host.

Entity Beans ? Signifies one to row on database

0 contains session kidney beans, organization kidney beans just weren’t incorporated. Organization beans was basically put in type 1.1 and this appeared while in the season 1999. Current discharge is actually EJB variation step one.2

Features off EJB? Databases administration –Databases relationship pooling –DataSource, provided by the latest J2EE server. Necessary to accessibility union pool of the server. –Database access was configured on J2EE machine -> simple to change database / databases rider Deal administration –Marketed transactions –J2EE servers has the benefit of transaction monitor that will be utilized because of the client. Protection government –Authetication –Agreement –security Organization coffee beans would be marketed /replicated into the separate machines

lDistribution/duplication also provides –Weight balancing, stream are going to be split up into independent server. –Failover, if an individual server fails, anyone else are able to keep with the handling normally. –Results, you to servers isn’t thus heavy piled. Plus, such as for instance Weblogic has actually bond swimming pools having improving results in one single servers.

When you should like EJB? Host would-be heavy piled –Shipments regarding servers helps to reach best results. Machine should have imitation towards the case of inability of a single server. –Replication is actually invisible into the designer Marketed purchases are required –J2EE host now offers purchase monitor that takes proper care of transaction administration. –Delivered transactions try undetectable on the designer ? Most other functions vs. currency Weblogic J2EE host

Why not to make use of 100 % free J2EE servers? –no tecnical support –more complicated to utilize (no user interface . ) –zero consolidation so you can development devices (like, Jbuilder) –Pests? Other difficulties during the investment?

Alternative:Tuxedo ? Tuxedo are good middleware that offers scalability functions and you can exchange checks. ? C or C++ built. ? May be used that have Coffees buyer because of the groups inside the JOLT bundle offered by BEA. Smaller that J2EE machine?

J2EE server also offers ? DataSource. –Target which you can use to reach databases connection on the partnership pool. –Are going to be reached of the software DataSource ? Deal display screen –Can be reached from the screen UserTransaction. ? Java Naming plus the Directory Service

Java Naming while the Directory Service ? Naming solution must to acquire beans household connects or any other things (DataSource, UserTransaction) –Such as, jndi name of your DataSource ? Index solution must store and recover characteristics of the their name. –jndi title: java:comp/env/propertyName

XML – deployment descriptor ejb-jar.xml + server-certain xml- file Which is up coming Packed from inside the a container – file including bean categories. Beans are manufactured for the EJB Jar file , Reveal document is utilized to help you number EJB’s and you will jar document carrying Implementation descriptor.

Session Bean Developer programs about three categories: –Domestic program, consists of methods for doing (and you may finding for entity kidney beans) bean era. –Secluded program, consists of organization measures the fresh bean offers. –Bean classification, provides the business reasoning of your own organization bean.

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