Piero Steffano Del Aguila Macher

Last Time we learned how to configure a hibernate+ spring+ GWT application. Now we will continue explaining how I built this  application. First, we'll start with the Beans. For this example we will define one bean called Regions and an interface called Bean . Region will be the pojo class that contains the mapping for HR schema regions table The  @Entity  annotation is used to mark this class as an Entity bean. To use this annotation the class must have at least a package scope no-argument constructor. The  @Table  annotation is used to specify the table to persist the data. The  name  attribute refers to the table name. If  @Table  annotation is not specified then Hibernate will by default use the class name as the table name. The  @Id  annotation is used to specify the identifier property of the entity bean. The placement of the @Id  annotation determines the default access strategy that Hibernate will use f...

Building a web application using hibernate, spring and gwt. This time we will show how to create and cofigure an application that will use hibernate , spring and gwt. I will use HR sample database that comes with OracleXE. First , you have to create a GWT project (you can follow the steps for that on  https://developers.google.com/web-toolkit/ ) After you have the project created you need to create a tree of packages like that: Open HumanResources.gwt.xml and add the following line : By doing that you tell gwt to include model package and all dependent packages into gwt compilation Now we can start configuring spring and hibernate. to configure spring first you have to add the following lines on web.xml This will allow spring context to start doing its business. The you will have to create a field called "app-config.xml" in which you will define the settings for spring and hibernate. Over this app-config file first configure the properties as follo...

I've found an interesting and easy to understand explanation about volatile keyword, it came with an example but it was wrong so I've corrected it. A volatile variable does not have a copy maintained in the local memory of the thread (on the stack). All changes to the volatile variable (caused by multiple threads) are flushed out to the heap memory (visible from all threads). Hence volatile variable values remain consistent for all threads.  On the other hand, for other instance variables, each java thread maintains a local copy on the stack. Multiple threads may modify this local copy of the instance variable and hence inconsistent values may be visible for multiple threads.  For preventing this condition, we synchronize. During synchronization, a lock is first taken on the object monitor. Then the thread reads the state from the main memory and flushes its internal state. Subsequently, the synchronized code block/method code is executed. Once the execution completes, al...

Calling a rest service with spring rest + json jackson Presenting to you step by step a tutorial about the use of some apis that leverage the logic for calling to a rest service and also the json parting and marshalling process First Step Importing required libs: You will need to import spring for droid there are the files: spring-android-auth-1.0.0.M4.jar spring-android-core-1.0.0.M4.jar spring-android-rest-template-1.0.0.M4.jar You will need to import jackson lib there is the file: jackson-all-1.9.4.jar Second Step : Declaring variables You will need these three variables to do the trick. I will recomend to declare them as fields and instantiate them later on class constructor. RestTemplate restTemplate = new RestTemplate(); ObjectMapper objectMapper = new ObjectMapper(); JsonFactory jsonFactory = new JsonFactory(); Third step: Calling rest service: Just call this method of rest template and the api will call the service and will encapsulate all the stream st...