Singh Harmeet

Very Welcome Frits-Johan Walraven in ranch.

thank you Mr Bobby Jakachira , for all answers of my Queries .. very - 2 thank full to you..

i have a scanner of this type. how to manage the input using bar code scanner in our java program ?

i am confused , in pro JPA book , there are one chapter that mention the session beans and transaction . in JPA exam how many questions are related with EJB session beans and and how many related with Transaction management ?

Singh Harmeet wrote:in JPA the persistence context and persistence unit have one to one relation(this is not rdbms relation) . the persistence context is used to manipulate the entities operations and persist the entities who are available in persistence context . the @PersistenceContext annotation is mostly used with JavaEE container , in which the persistence context is automatically managed by container. persistence context need the reference of persistence unit , because in the persistence unit we mention all the entities and transaction type etc . @PersistenceContext have unitName attribute to take the reference of persistence unit.

the JPA the persistence context and persistence unit have one to one relation(this is not rdbms relation) . the persistence context is used to manipulate the entities operations and persist the entities who are available in persistence context . the @PersistenceContext annotation is mostly used with JavaEE container , in which the persistence context is automatically managed by container. persistence context need the reference of persistence unit , because in the persistence unit we mention all the entities and transaction type etc . @PersistenceContext have unitName attribute to take the reference of persistence unit.

in the JTA transaction , when the transaction is failed , the container automatically roll back the transaction . when the exception is throw the EJBContext class setRollBackOnly() method automatically call to roll back the transaction.

thanks to all .....

i am new for java server socket programming . i want to build an small client server application in java . in this application the client is web browser and server is core java program . i am little bit know about command line client program that deal with java server . but with web browser i have no idea.

in JPA specifications , there is examples problems . the examples are not clear.

congrat's for passing certification . but in pro JPA the examples are not full define , in chapter 10 i face many problems , is there any other book instead of PRO JPA 2 ?

i prepare my self of OCE-JPA certification , in PRO JPA 2 book chapter 5 , explain the Map<> use in OneToMany relationship between Entities . when i try to insert the element in Map<String ,String> there is fowling exception throw. Exception in thread "main" org.hibernate.HibernateException: null index column for collection . please explain the exception and explain how to use Map<> in relationship , with small example.

please explain the name of the book , written by Michael's Sybex.

i understand but it is the project requirement. so we need to learn SOAP with core java.

i m new in java web services . i have a core java project need to implement SOAP web services in project. from where i start to learn SOAP and How to integrate with core java?