Hibernate

Hibernate 3.0, the latest Open Source persistence technology at the heart of J2EE EJB 3.0 is available for download from Hibernet.org.The Hibernate 3.0 core is 68,549 lines of Java code together with 27,948 lines of unit tests, all freely available under the LGPL, and has been in development for well over a year. Hibernate maps the Java classes to the database tables. It also provides the data query and retrieval facilities that significantly reduces the development time.  Hibernate is not the best solutions for data centric applications that only uses the stored-procedures to implement the business logic in database. It is most useful with object-oriented domain modes and business logic in the Java-based middle-tier. Hibernate allows transparent persistence that enables the applications to switch any database. Hibernate can be used in Java Swing applications, Java Servlet-based applications, or J2EE applications using EJB session beans.

Features of Hibernate

• Hibernate 3.0 provides three full-featured query facilities: Hibernate Query Language, the newly enhanced Hibernate Criteria Query API, and enhanced support for queries expressed in the native SQL dialect of the database.
    
• Filters for working with temporal (historical), regional or permissioned data.
   
• Enhanced Criteria query API: with full support for projection/aggregation and subselects.
    
• Runtime performance monitoring: via JMX or local Java API, including a second-level cache browser.
    
• Eclipse support, including a suite of Eclipse plug-ins for working with Hibernate 3.0, including mapping editor, interactive query prototyping, schema reverse engineering tool.
   
• Hibernate is Free under LGPL: Hibernate can be used to develop/package and distribute the applications for free.
   
• Hibernate is Scalable: Hibernate is very performant and due to its dual-layer architecture can be used in the clustered environments.
    
• Less Development Time: Hibernate reduces the development timings as it supports inheritance, polymorphism, composition and the Java Collection framework.
    
• Automatic Key Generation: Hibernate supports the automatic generation of primary key for your.
    
•  JDK 1.5 Enhancements: The new JDK has been released as a preview earlier this year and we expect a slow migration to the new 1.5 platform throughout 2004. While Hibernate3 still runs perfectly with JDK 1.2, Hibernate3 will make use of some new JDK features. JSR 175 annotations, for example, are a perfect fit for Hibernate metadata and we will embrace them aggressively. We will also support Java generics, which basically boils down to allowing type safe collections.
   
• EJB3-style persistence operations: EJB3 defines the create() and merge() operations, which are slightly different to Hibernate's saveOrUpdate() and saveOrUpdateCopy() operations. Hibernate3 will support all four operations as methods of the Session interface.
    
• Hibernate XML binding enables data to be represented as XML and POJOs interchangeably.
    
• The EJB3 draft specification support for POJO persistence and annotations.

How many modules are there in Spring? What are they?

Spring comprises of seven modules. They are.. 

• The core container:
  The core container provides the essential functionality of the Spring framework. A primary component of the core container is the BeanFactory, an implementation of the Factory pattern. The BeanFactory applies the Inversion of Control (IOC) pattern to separate an application's configuration and dependency specification from the actual application code.
• Spring context:
  The Spring context is a configuration file that provides context information to the Spring framework. The Spring context includes enterprise services such as JNDI, EJB, e-mail, internalization, validation, and scheduling functionality.
• Spring AOP:
  The Spring AOP module integrates aspect-oriented programming functionality directly into the Spring framework, through its configuration management feature. As a result you can easily AOP-enable any object managed by the Spring framework. The Spring AOP module provides transaction management services for objects in any Spring-based application. With Spring AOP you can incorporate declarative transaction management into your applications without relying on EJB components.
• Spring DAO:
  The Spring JDBC DAO abstraction layer offers a meaningful exception hierarchy for managing the exception handling and error messages thrown by different database vendors. The exception hierarchy simplifies error handling and greatly reduces the amount of exception code you need to write, such as opening and closing connections. Spring DAO's JDBC-oriented exceptions comply to its generic DAO exception hierarchy.
• Spring ORM:
  The Spring framework plugs into several ORM frameworks to provide its Object Relational tool, including JDO, Hibernate, and iBatis SQL Maps. All of these comply to Spring's generic transaction and DAO exception hierarchies.
• Spring Web module:
  The Web context module builds on top of the application context module, providing contexts for Web-based applications. As a result, the Spring framework supports integration with Jakarta Struts. The Web module also eases the tasks of handling multi-part requests and binding request parameters to domain objects.
• Spring MVC framework:
  The Model-View-Controller (MVC) framework is a full-featured MVC implementation for building Web applications. The MVC framework is highly configurable via strategy interfaces and accommodates numerous view technologies including JSP, Velocity, Tiles, iText, and POI.

Spring Framework

Spring framework is developed to simplify the developed of enterprise applications in Java technologies. It is an open source framework begin developed by Spring source company. Spring framework is also available for .NET framework (Spring .NET).

The Spring is light weight, non-invasive IoC Container and AOP framework. It provides support for JPA, Hibernate, Web services, Schedulers, Ajax, Struts, JSF and many other frameworks. The Spring MVC components can be used to developed MVC based web applications. Spring framework provides many features that makes the development of enterprise application easy work.

What is Spring?

Spring is an open source framework created to address the complexity of enterprise application development. One of the chief advantages of the Spring framework is its layered architecture, which allows you to be selective about which of its components you use while also providing a cohesive framework for J2EE application development. 

What are the advantages of Spring framework?

The advantages of Spring are as follows:

• Spring has layered architecture. Use what you need and leave you don't need now.
• Spring Enables POJO Programming. There is no behind the scene magic here. POJO programming enables continuous integration and testability.
• Dependency Injection and Inversion of Control Simplifies JDBC
• Open source and no vendor lock-in
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• What are features of Spring ?
• Lightweight:
  spring is lightweight when it comes to size and transparency. The basic version of spring framework is around 1MB. And the processing overhead is also very negligible.
• Inversion of control (IOC):
  Loose coupling is achieved in spring using the technique Inversion of Control. The objects give their dependencies instead of creating or looking for dependent objects.
• Aspect oriented (AOP):
  Spring supports Aspect oriented programming and enables cohesive development by separating application business logic from system services.
• Container:
  Spring contains and manages the life cycle and configuration of application objects.
• MVC Framework:
  Spring comes with MVC web application framework, built on core Spring functionality. This framework is highly configurable via strategy interfaces, and accommodates multiple view technologies like JSP, Velocity, Tiles, iText, and POI. But other frameworks can be easily used instead of Spring MVC Framework.
• Transaction Management:
  Spring framework provides a generic abstraction layer for transaction management. This allowing the developer to add the pluggable transaction managers, and making it easy to demarcate transactions without dealing with low-level issues. Spring's transaction support is not tied to J2EE environments and it can be also used in container less environments.
• JDBC Exception Handling:
  The JDBC abstraction layer of the Spring offers a meaningful exception hierarchy, which simplifies the error handling strategy. Integration with Hibernate, JDO, and iBATIS: Spring provides best Integration services with Hibernate, JDO and iBATIS
   

 

Spring Framework