What is an EJB, and what does it do? - Stack Overflow
The lifecycle of EJBs is container managed. As required, it creates EJB instances, clears and initializes stateful session bean state, passivates & activates, and calls lifecycle callback methods, so EJB code can participate in lifecycle operations to acquire and release resources, or perform other initialization and shutdown behavior.
java - What does the @EJBs annotation do? - Stack Overflow
I had a web project, jee 6, with ejbs in it and i didnt have to specify name attribute with @EJB, once I moved ejbs to separate ejb jar (still same ear) weblogic 12.1.2 tells me "The ejb-ref does not have an ejb-link and the JNDI name of the target Bean has not been specified" –
java - Why should we use EJB? - Stack Overflow
Connection Pool to Database. All ejb can access to connection pools defined into the Java EE Application Server, this connection pools provide an abstraction of the database complexity, by example you can use a XA Datasource that enables to you do Two Phased Commit to different databases. Security. All ejb can use JAAS for secure the applications.
Web Services vs EJB vs RMI, advantages and disadvantages?
2010年1月6日 · Between EJB and RMI, EJB would certainly be better - it has everything RMI has and much more via the container (object pooling, transaction management, etc.) Between EJB and web services, web services would give you more portability if you want to be able to call them from non-java apps in the future.
java - Difference between Javabean and EJB - Stack Overflow
2009年9月1日 · EJB technology enables rapid and simplified development of distributed, transactional, secure, and portable applications based on Java EE 6 technology. In simple language: If you create an EJB and deploy it on server, it can be called remotely (using some technique, i.e. JNDI lookup using RMI) or locally (i.e. with in an application).
What is the difference between @Inject and @EJB
2016年5月10日 · Yes, the CDI container knows whether a type is an EJB interface, so it will still coordinate with the EJB container to obtain an EJB proxy, which allows the EJB container to control the actual bean lifecycle, and then the CDI container will wrap the EJB proxy with a CDI proxy as needed (e.g., contextual proxy is meaningless for a stateless bean but meaningful for …
EJB @Schedule wait until method completed - Stack Overflow
2016年10月7日 · "the second bean is needed because EJB 3.1 does not allow upgrading a read lock to a write lock" - It's not so much that it is unsupported, it is inherently impossible to do that bug-free. Whenever two readers concurrently wait to be upgraded, they deadlock each other, because neither can upgrade while the other still holds the lock in read-mode.
java - Should I use @EJB or @Inject - Stack Overflow
The @EJB is used to inject EJB's only and is available for quite some time now. @Inject can inject any managed bean and is a part of the new CDI specification (since Java EE 6). In simple cases you can simply change @EJB to @Inject .
java - How does EJB and JPA relate? - Stack Overflow
2017年1月1日 · EJB uses or enables the usage of JPA in its specification, simply because JPA is a good standard. You can now switch between JPA vendors without changing your code if designed properly. EJB specification can be used independent of JPA (although JPA has been included as a part of EJB spec) and likewise JPA can be used for many more stuff outside ...
@Inject, @EJB, @Local, @Remote, @LocalBean, etc... : confused?
2016年1月11日 · From WAR to EJB-JAR of EAR, make a JNDI lookup to the remote interface. From EJB-JAR to EJB-JAR, make an injection via "@EJB" to the local interface. For two services within the same EJB-JAR, make an injection via "@Inject" to the local interface. What do you think about it? Is it correct?