Welcome!

Java IoT Authors: Liz McMillan, Pat Romanski, Yeshim Deniz, Elizabeth White, Kong Yang

Related Topics: Java IoT

Java IoT: Article

Spring and Java EE 5 (PART 1)

Simplicity and power combined

Register for Real-World Java Seminar

The Java Platform, Enterprise Edition, or Java EE, is the most popular middleware platform for developing and deploying enterprise applications. Java EE offers developers a choice of vendors, portability, scalability, and robustness. However, it has been criticized for its complexity and its need for a lot of redundant and procedural code. In addition, lightweight frameworks such as Spring and scripting platforms such as Ruby on Rails have emerged to challenge the platform's supremacy in the middleware world.

In response, the Java Community Process has made great efforts to simplify the developer's life with Java EE's latest incarnation: Java EE 5. Innovations such as radically simplified models for Enterprise JavaBeans (EJB) and Web services have changed how enterprise applications are built using Java EE 5 technologies. Combining the robustness of the Java EE platform with lightweight frameworks such as Spring further enables developers to rapidly develop portable, maintainable enterprise applications.

In this two-part series, I will discuss how Java EE 5 simplifies enterprise application development, then uncover how you can utilize the Spring Framework to fill the gaps left by Java EE 5.

Simplified Programming Model with Java EE 5
Java EE 5 radically simplifies the development of enterprise applications by:

  • Adopting a plain old Java object (POJO) programming standard and setting intelligent defaults for EJB components
  • Eliminating the need for deployment descriptors and using Java metadata annotations for deployment settings instead
  • Introducing a simplified POJO persistence model similar to Oracle TopLink and JBoss Hibernate
  • Using dependency injection instead of the Java Naming and Directory Interface (JNDI) to locate resources and EJB components

Let's briefly examine these changes.

Simplified Persistence
Most developers who used the EJB 2 container-managed persistence were disappointed with its complexity and performance. As a result, POJO persistence frameworks such as Hibernate and TopLink became popular, compelling the Java Community Process to standardize a persistence API for the Java platform on a POJO persistence model.

If you've used an object-relational (O/R) mapping framework to build the persistence tier of your application, you'll notice that each framework provides three facilities:

  • A declarative way to perform O/R mapping. This method, called O/R mapping metadata, lets you map an object to one or more database tables. Most O/R frameworks use XML for storing O/R mapping metadata.
  • An API to manipulate entities (for example, to perform create, read, update, and delete - or CRUD - operations). The API lets you persist, retrieve, update, or remove objects. Based on the use of the API and the O/R mapping metadata, the O/R framework performs database operations on your behalf. The API shields you from writing Java Database Connectivity (JDBC) or SQL code to persist your domain objects.
  • A query language to retrieve objects. This is one of the most important aspects of persistence because improper SQL statements may slow down your database. A query language also protects your applications from being cluttered with proprietary SQL, and lets you retrieve entities or objects without writing SQL SELECT statements.

The EJB 3 Java Persistence API (JPA) standardizes the use of persistence for the Java platform by providing a standard mechanism for O/R mapping, an EntityManager API to perform CRUD operations, and a way to extend the EJB query language (EJB-QL) to retrieve entities.

Introducing JPA Entities
An entity is a lightweight domain object - a plain old Java object that you want to persist in a relational database. Like any POJO, an entity may be either an abstract or a concrete class, and it can extend another POJO. You can use the @javax.persistence.Entity annotation to mark a POJO to be an entity, as shown in Listing 1.

(The code examples that follow are taken from my recently published book, EJB 3 in Action, published by Manning Publications.)

I've used annotations to define the mapping of entities to tables; you can also use XML. It's worth mentioning that JPA provides support for rich domain modeling capabilities such as inheritance, and polymorphism. JPA supports several inheritance mapping strategies: single table, joined subclass, and table per class. Unlike EJB 2 container-managed persistence (CMP), JPA is simple and supports automatic generation of primary keys.

Now that you've seen an entity, let's examine how you can manipulate entities by using the EntityManager API.

The EntityManager API
The javax.persistence.EntityManager manages entity lifecycles and exposes several methods to perform CRUD operations on entities. JPA supports two types of EntityManager: container-managed and application-managed. The application-managed EntityManager is really useful when using JPA outside a container. Let's look at an example of using a container-managed EntityManager to manage an entity.

You can use the persist() method to save an instance of entity. For example, if you want to persist an instance of Bid, use the following code:

@PersistenceContext(unitName="actionBazaar")
private EntityManager em;
...
Bid bid = new Bid();
bid.setItem(item);
bid.setBidder(bidder);
bid.setBidPrice(price);
em.persist(bid);

Now that you have a sense of how easy it is to use the persistence feature of EJB 3, we'll examine how EJB 3 simplifies the development of business components.

Simplified EJB 3 Components
EJB 2 was one of the primary technologies responsible for the complexities that have plagued enterprise Java development. Some detractors ridiculed it as a "fat elephant" for its heavyweight nature. It required a lot of redundant code, even to build a simple "HelloWorld" EJB.

EJB 3 simplifies development by adopting the POJO programming model, and simplifies usage of EJB and resources by using dependency injection. It also depends heavily on intelligent defaults and makes the deployment descriptor optional.

Listing 2 provides an example of a simple stateless EJB 3 session bean with a remote interface. In this example, PlaceBidBean is a simple POJO class that implements a regular Java interface - or a plain old Java interface (POJI). The @javax.ejb.Remote converts the POJI to a remote interface and @javax.ejb.Stateless converts the POJO to a stateless EJB.

You can use @Stateful and @MessageDriven annotations to define stateful and message-driven beans, respectively.

More Stories By Debu Panda

Debu Panda is a Director of Product Management at Oracle Corporation. He is lead author of the EJB 3 in Action (Manning Publications) and Middleware Management (Packt). He has more than 20 years of experience in the IT industry and has published numerous articles on enterprise Java technologies and has presented at many conferences. Debu maintains an active blog on enterprise Java at http://debupanda.blogspot.com.

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


@ThingsExpo Stories
"When we talk about cloud without compromise what we're talking about is that when people think about 'I need the flexibility of the cloud' - it's the ability to create applications and run them in a cloud environment that's far more flexible,” explained Matthew Finnie, CTO of Interoute, in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
The Internet giants are fully embracing AI. All the services they offer to their customers are aimed at drawing a map of the world with the data they get. The AIs from these companies are used to build disruptive approaches that cannot be used by established enterprises, which are threatened by these disruptions. However, most leaders underestimate the effect this will have on their businesses. In his session at 21st Cloud Expo, Rene Buest, Director Market Research & Technology Evangelism at Ara...
The current age of digital transformation means that IT organizations must adapt their toolset to cover all digital experiences, beyond just the end users’. Today’s businesses can no longer focus solely on the digital interactions they manage with employees or customers; they must now contend with non-traditional factors. Whether it's the power of brand to make or break a company, the need to monitor across all locations 24/7, or the ability to proactively resolve issues, companies must adapt to...
The current age of digital transformation means that IT organizations must adapt their toolset to cover all digital experiences, beyond just the end users’. Today’s businesses can no longer focus solely on the digital interactions they manage with employees or customers; they must now contend with non-traditional factors. Whether it's the power of brand to make or break a company, the need to monitor across all locations 24/7, or the ability to proactively resolve issues, companies must adapt to...
Artificial intelligence, machine learning, neural networks. We’re in the midst of a wave of excitement around AI such as hasn’t been seen for a few decades. But those previous periods of inflated expectations led to troughs of disappointment. Will this time be different? Most likely. Applications of AI such as predictive analytics are already decreasing costs and improving reliability of industrial machinery. Furthermore, the funding and research going into AI now comes from a wide range of com...
In this presentation, Striim CTO and founder Steve Wilkes will discuss practical strategies for counteracting fraud and cyberattacks by leveraging real-time streaming analytics. In his session at @ThingsExpo, Steve Wilkes, Founder and Chief Technology Officer at Striim, will provide a detailed look into leveraging streaming data management to correlate events in real time, and identify potential breaches across IoT and non-IoT systems throughout the enterprise. Strategies for processing massive ...
SYS-CON Events announced today that GrapeUp, the leading provider of rapid product development at the speed of business, will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Grape Up is a software company, specialized in cloud native application development and professional services related to Cloud Foundry PaaS. With five expert teams that operate in various sectors of the market acr...
Internet of @ThingsExpo, taking place October 31 - November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 21st Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The Internet of Things (IoT) is the most profound change in personal and enterprise IT since the creation of the Worldwide Web more than 20 years ago. All major researchers estimate there will be tens of billions devic...
SYS-CON Events announced today that Ayehu will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on October 31 - November 2, 2017 at the Santa Clara Convention Center in Santa Clara California. Ayehu provides IT Process Automation & Orchestration solutions for IT and Security professionals to identify and resolve critical incidents and enable rapid containment, eradication, and recovery from cyber security breaches. Ayehu provides customers greater control over IT infras...
SYS-CON Events announced today that MobiDev, a client-oriented software development company, will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. MobiDev is a software company that develops and delivers turn-key mobile apps, websites, web services, and complex software systems for startups and enterprises. Since 2009 it has grown from a small group of passionate engineers and business...
SYS-CON Events announced today that Cloud Academy named "Bronze Sponsor" of 21st International Cloud Expo which will take place October 31 - November 2, 2017 at the Santa Clara Convention Center in Santa Clara, CA. Cloud Academy is the industry’s most innovative, vendor-neutral cloud technology training platform. Cloud Academy provides continuous learning solutions for individuals and enterprise teams for Amazon Web Services, Microsoft Azure, Google Cloud Platform, and the most popular cloud com...
SYS-CON Events announced today that CA Technologies has been named "Platinum Sponsor" of SYS-CON's 21st International Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. CA Technologies helps customers succeed in a future where every business - from apparel to energy - is being rewritten by software. From planning to development to management to security, CA creates software that fuels transformation for companies in the applic...
We build IoT infrastructure products - when you have to integrate different devices, different systems and cloud you have to build an application to do that but we eliminate the need to build an application. Our products can integrate any device, any system, any cloud regardless of protocol," explained Peter Jung, Chief Product Officer at Pulzze Systems, in this SYS-CON.tv interview at @ThingsExpo, held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA
SYS-CON Events announced today that IBM has been named “Diamond Sponsor” of SYS-CON's 21st Cloud Expo, which will take place on October 31 through November 2nd 2017 at the Santa Clara Convention Center in Santa Clara, California.
Amazon started as an online bookseller 20 years ago. Since then, it has evolved into a technology juggernaut that has disrupted multiple markets and industries and touches many aspects of our lives. It is a relentless technology and business model innovator driving disruption throughout numerous ecosystems. Amazon’s AWS revenues alone are approaching $16B a year making it one of the largest IT companies in the world. With dominant offerings in Cloud, IoT, eCommerce, Big Data, AI, Digital Assista...
SYS-CON Events announced today that Enzu will exhibit at SYS-CON's 21st Int\ernational Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Enzu’s mission is to be the leading provider of enterprise cloud solutions worldwide. Enzu enables online businesses to use its IT infrastructure to their competitive advantage. By offering a suite of proven hosting and management services, Enzu wants companies to focus on the core of their ...
Multiple data types are pouring into IoT deployments. Data is coming in small packages as well as enormous files and data streams of many sizes. Widespread use of mobile devices adds to the total. In this power panel at @ThingsExpo, moderated by Conference Chair Roger Strukhoff, panelists looked at the tools and environments that are being put to use in IoT deployments, as well as the team skills a modern enterprise IT shop needs to keep things running, get a handle on all this data, and deliver...
In his session at @ThingsExpo, Eric Lachapelle, CEO of the Professional Evaluation and Certification Board (PECB), provided an overview of various initiatives to certify the security of connected devices and future trends in ensuring public trust of IoT. Eric Lachapelle is the Chief Executive Officer of the Professional Evaluation and Certification Board (PECB), an international certification body. His role is to help companies and individuals to achieve professional, accredited and worldwide re...
IoT solutions exploit operational data generated by Internet-connected smart “things” for the purpose of gaining operational insight and producing “better outcomes” (for example, create new business models, eliminate unscheduled maintenance, etc.). The explosive proliferation of IoT solutions will result in an exponential growth in the volume of IoT data, precipitating significant Information Governance issues: who owns the IoT data, what are the rights/duties of IoT solutions adopters towards t...
With the introduction of IoT and Smart Living in every aspect of our lives, one question has become relevant: What are the security implications? To answer this, first we have to look and explore the security models of the technologies that IoT is founded upon. In his session at @ThingsExpo, Nevi Kaja, a Research Engineer at Ford Motor Company, discussed some of the security challenges of the IoT infrastructure and related how these aspects impact Smart Living. The material was delivered interac...