Alejandro Gervasio is a senior System Analyst from Argentina who has been involved in software development since the mid-80's. He has more than 12 years of experience in PHP development, 10 years in Java Programming, Object-Oriented Design, and most of the client-side technologies available out there.
Alejandro's articles
Using Java Bean Validation for Method Parameters and Return Values
By Alejandro Gervasio,
Validate arguments and return values of methods and constructors with Bean Validation's ExecutableValidator and automate it with Java EE interceptors.
Three Design Patterns That Use Inversion of Control
By Alejandro Gervasio,
Inversion of control is not just dependency injection - the observer and template method patterns use it as well. Study all three to become an IoC expert!
Validate Object Graphs with Java Bean Validation’s @Valid Annotation
By Alejandro Gervasio,
Use Java Bean Validation's @Valid Annotation for validating entire object graphs with one method call.
Java Bean Validation’s validateProperty() and validateValue() in Three Minutes
By Alejandro Gervasio,
Use the Java Bean Validation methods validateValue() and validateProperty() to independently check fields of a target class or even their potential values.
Using CDI/Weld to Inject JPA/Hibernate Entity Managers
By Alejandro Gervasio,
A tutorial on how to use Contexts and Dependency Injection (CDI) / Weld and Hibernate in the development of a full-blown JPA application.
Introduction to Contexts and Dependency Injection (CDI)
By Alejandro Gervasio,
A tutorial on how to use Contexts and Dependency Injection (CDI) and Weld in Java SE, covering core features like annotations, qualifiers, and producers.
Effective Domain Model Validation with Hibernate Validator
By Alejandro Gervasio,
A hands-on guide to domain model validation with the Java Beans Validation standard (JSR 303) and Hibernate Validator (Apache BVal is very similar.)
Building a Web App with Java Servlets
By Alejandro Gervasio,
This tutorial builds a simple Java web application with Java's Servlet API. It shows how to set the project up, create views / controllers, and deploy.
A Hibernate Introduction – Persisting Java Objects the Easy Way
By Alejandro Gervasio,
JPA/Hibernate is a common approach to persistence in Java. This tutorial creates a simple CRUD app using Hibernate's EntityManager and the DAO pattern.
Inversion of Control – The Hollywood Principle
By Alejandro Gervasio,
Although the "Dependency Injection = Inversion of Control" equation can generally be considered valid, the concept of IoC is actually much broader.