T R A N S A C T I O N S  

Lock

Thread 1

Bean A

Lock

Bean B

Thread 2

In JBoss 3.0 there is a deadlock detection system in place, which will throw a deadlock 

exception on one of the threads freeing the other thread to call the other bean. Now the 

caller of the interrupted thread receives the exception and can decide to retry the call, to go 

over and throw an exception as well. 

Example 

Derived from the Template the Transaction example mimics a bank where you have banks, 

customers, accounts and tellers. The CMP Entity Beans are hidden behind Session Beans, 

which contains the business logic, and should only be accessed by them. 

Because in this example as well XDoclet is used the specification of the transaction 

attributes is very simple: 

/** 

 * The Session bean represents the customer s business interface 

 * @ejb:transaction type="Required" 

 */ 

public class CustomerSessionBean 

   extends SessionSupport 

{ 

   /** 

    * @ejb:interface method view type="remote" 

    * @ejb:transaction type="RequiresNew" 

    **/ 

   public CustomerData createCustomer( 

      String pBankId, String pName, float pInitialDeposit 

   ) 

      throws CreateException, RemoteException 

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