zxing qr code reader java Understanding object/relational persistence in Java

Implementation QR Code ISO/IEC18004 in Java Understanding object/relational persistence

Thankfully, you can use the standard APIs provided by the J2EE framework to solve the majority of concurrency-related problems. JMS and message-driven beans simplify asynchronous invocations and executing concurrent processes. You have both the Java Management Extensions (JMX) and EJB 2.1 timer services, which you can use to schedule system- and business logic-related tasks, respectively. Vendor-specific APIs usually fill in the remaining holes, enabling developers to utilize the application server s thread management infrastructure. In this case, the application designer must weigh the risks of disrupting the server s runtime environment with foreign threads against those of binding the code to a proprietary

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The order in which routes are added to the route table determines the order in which they ll be searched when looking for a match. This means routes should be listed in source code from highest priority with the most specific conditions down to lowest priority, or a catchall route. This is a common place for routing bugs to appear. Watch out for them!

In JBoss Seam, you no longer need to use the Search wrapping methods. This makes the code slightly more natural. We now have access to the right API. Let s create a Hibernate Search query.

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* MatchingTask Tasks denoted with the asterisk (*) also support the follow attributes and subelements. These tasks operate on an implicit fileset, and typically have an attribute representing the base directory of the fileset.

We discussed the client lifecycle of an ASP.NET AJAX page in chapter 2. Be sure you understood the material presented there before you proceed. After this overview of the client component model, you re ready to start working with client components; let s shift from theory to practice by creating your first trivial component.

By default, some of the relationship types are retrieved lazily while some are loaded eagerly. We ll discuss why each default makes sense as we go through each relationship retrieval case for the Item entity. The Seller associated with an Item is retrieved eagerly, because the fetch mode for the @ManyToOne annotation is defaulted to EAGER. To understand why this make sense, it is helpful to understand how the EntityManager implements eager fetching. In effect, each eagerly fetched relationship turns into an additional JOIN tacked onto the basic SELECT statement to retrieve the entity. To see what we mean, let s see how the SELECT statement for an eagerly fetched Seller record related to an Item looks (listing 9.9).