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Changes for Hibernate 3.5 applications

if your application uses Hibernate 3 classes that are not available in Hibernate 4, for example, some of the validator or search classes, you may see ClassNotFoundExceptions when you deploy your application. If you encounter this problem, you can try one of two approaches: You may be able to resolve the issue by copying the specific Hibernate 3 JARs containing those classes into the application "/lib" directory or by adding them to the classpath using some other method. In some cases this may result in ClassCastExceptions or other class loading issues due to the mixed use of the Hibernate versions, so you will need to use the second approach. You need to tell the server to use only the Hibernate 3 libraries and you will need to add exclusions for the Hibernate 4 libraries. Details on how to do this are described here: JPA Reference Guide.

In previous versions of the application server, the JCA data source configuration was defined in a file with a suffix of *-ds.xml. This file was then deployed in the server's deploy directory. The JDBC driver was copied to the server lib/ directory or packaged in the application's WEB-INF/lib/ directory. In AS7, this has all changed. You will no longer package the JDBC driver with the application or in the server/lib directory. The *-ds.xml file is now obsolete and the datasource configuration information is now defined in the standalone/configuration/standalone.xml or in the domain/configuration/domain.xml file. A JDBC 4-compliant driver can be installed as a deployment or as a core module. A driver that is JDBC 4-compliant contains a META-INF/services/java.sql.Driver file that specifies the driver class name. A driver that is not JDBC 4-compliant requires additional steps, as noted below.

DataSource Configuration

domain mode, the configuration file is the domain/configuration/domain.xml

standalone mode, you will configure the datasource in the standalone/configuration/standalone.xml

MySQL datasource element:

        <connection-url>jdbc:mysql://localhost:3306/YourApplicationURL</connection-url>        <driver-class> com.mysql.jdbc.Driver </driver-class>        <driver> mysql-connector-java-5.1.15.jar </driver>

       <security>            <user-name> USERID </user-name>            <password> PASSWORD</password>        </security>

example of the driver element for driver that is not JDBC 4-compliant. The driver-class must be specified since it there is no META-INF/services/java.sql.Driver file that specifies the driver class name.

 <driver-class>com.mysql.jdbc.Driver</driver-class>

JDBC driver can be installed into the container in one of two ways: either as a deployment or as a core module

Install the JDBC driver

Install the JDBC driver as a deployment

In AS7 standalone mode, you simply copy the JDBC 4-compliant JAR into the AS7_HOME/standalone/deployments directory

example of a MySQL JDBC driver installed as a deployment:     AS7_HOME/standalone/deployments/mysql-connector-java-5.1.15.jar

this annotation bypasses the management layer and as such it is recommended only for development and testing purposes

Defining a Managed DataSource

Installing a JDBC driver as a deployment

Installing the JDBC Driver

deployment or as a core module

managed by the application server (and thus take advantage of the management and connection pooling facilities it provides), you must perform two tasks.  First, you must make the JDBC driver available to the application server; then you can configure the data source itself.  Once you have performed these tasks you can use the data source via standard JNDI injection.

recommended way to install a JDBC driver into the application server is to simply deploy it as a regular JAR deployment.  The reason for this is that when you run your application server in domain mode, deployments are automatically propagated to all servers to which the deployment applies; thus distribution of the driver JAR is one less thing for administrators to worry about.

Note on MySQL driver and JDBC Type 4 compliance: while the MySQL driver (at least up to 5.1.18) is designed to be a Type 4 driver, its jdbcCompliant() method always return false. The reason is that the driver does not pass SQL 92 full compliance tests, says MySQL. Thus, you will need to install the MySQL JDBC driver as a module (see below).

Installing a JDBC driver as a module

<module xmlns="urn:jboss:module:1.0" name="com.mysql">  <resources>    <resource-root path="mysql-connector-java-5.1.15.jar"/>  </resources>  <dependencies>    <module name="javax.api"/>  </dependencies></module>

jboss-7.0.0.<release>/modules/com/mysql/main

define your module with a module.xml file, and the actual jar file that contains your database driver

content of the module.xml file

Under the root directory of the application server, is a directory called modules

module name, which in this example is com.mysql

where the implementation is, which is the resource-root tag with the path element

define any dependencies you might have.  In this case, as the case with all JDBC data sources, we would be dependent on the Java JDBC API's, which in this case in defined in another module called javax.api, which you can find under modules/javax/api/main as you would expect.

Defining the DataSource itself

   <datasource jndi-name="java:jboss/datasources/MySqlDS" pool-name="MySqlDS">      <connection-url>jdbc:mysql://localhost:3306/EJB3</connection-url>         <driver>com.mysql</driver>

    <drivers>      <driver name="com.mysql" module="com.mysql">        <xa-datasource-class>com.mysql.jdbc.jdbc2.optional.MysqlXADataSource</xa-datasource-class>      </driver>    </drivers>

jboss-7.0.0.<release>/domain/configuration/domain.xml or jboss-7.0.0.<release>/standalone/configuration/standalone.xml

file listed under the filename parameter can be deployed to the server using the deploy goal

deploy

redeploy

undeploy

<phase>install</phase>

<goal>deploy</goal>

Deploying other artifacts

possible to deploy other artifacts that are not related to your deployment, e.g. database drivers:

<phase>install</phase>

<goal>deploy-artifact</goal>

<configuration> <groupId>postgresql</groupId> <artifactId>postgresql</artifactId> <name>postgresql.jar</name> </configuration>

artifact must be already listed as a dependency in the projects pom.xml.

Deploying your application in domain mode.

add the domain tag as well as specify at least one server group.

<domain> <server-groups> <server-group>main-server-group</server-group> </server-groups> </domain>

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not only code related

Code form

Architectural form

Testing form

Deployment form

Documentation form

Functional form

Project form

Organizational form

Whether technical dept is categorized as deliberate, inadvertent, reckless or careful, it is good to be aware of this and see how you want to cope with it strategically.

JBoss AS Tools

able to deploy my application directly from the workspace

bad news is that JBoss AS 7 does not currently support other persistence providers like Eclipselink, OpenJPA or DataNucleus

GlassFish and Resin, you can simply drop the JARs of your preferred provider and its dependencies in a designated folder of your server installation and edit your persistence.xml to override the default provider of the server

JBoss AS 7 appears to require an adapter per persistence provider, which to me looks like an unfortunate and unnecessary design decision

documentation continues to be sketchy and far below the standard of JBoss AS 5

top-level performance

classloader leaks

productivity issues of the Eclipse integration

lack of support for JPA providers other than Hibernate

Each of these is currently a blocker for using JBoss AS 7 in production

Redeployment

after a couple of redeployments, there was an OutOfMemoryError

new classloader leak

JBoss AS 7: Catching up with Java EE 6

Performance measurements

JBoss AS 7.0.2

GlassFish 3.1.1

Empty server startup time 1.9 s

3.2 s

Empty server heap memory 10.5 MB

26.5 MB

Empty server PermGen memory 36.3 MB

28.4 MB

MyApp deployment time 5.8 s

JBoss AS 7 is now at a competitive level with Resin and Glassfish and actually outperforms Glassfish in almost all of these tests

For example; certain procedures and workflows will need to be developed (new hire/leaver procedures for example)

The discussion whether or not to use Spring vs. Java EE for new enterprise Java applications is a no-brainer

Why migrate?

since then fallen a prey to the hungry minds of Venture Capitalists and finally into the hands of a virtualization company called VMware

While the different companies and individuals behind the Spring framework have been doing some work in the JCP their voting behavior on important JSRs is peculiar to say the least

outdated ORM solution like JDBC templates

some developers completely stopped looking at new developments in the Java EE space and might have lost track of the current state of technology

size of the deployment archive

fairly standard Java EE 6 application will take up about 100 kilobytes

comparable Spring application weighs in at a whopping 30 Megabytes!

Lightweight

Firing up the latest JBoss AS 7 Application Server from scratch and deploying a full blown Java EE 6 application into the server takes somewhere between two and five seconds on a standard machine. This is in the same league as a Tomcat / Spring combo

Dependency injection

Java EE 6, the Context and Dependency Injection (CDI) specification was introduced to the Java platform, which has a very powerful contextual DI model adding extensibility of injectable enterprise services

Aspect Oriented Programming

“AOP Light” and this is exactly what Java EE Interceptors do

common pitfall when taking AOP too far is that your code might end up all asymmetric and unreadable. This is due to the fact that the aspect and its implementation are not in the same place. Determining what a piece of code will do at runtime at a glance will be really hard

Testing

With Arquillian we can get rid of mocking frameworks and test Java EE components in their natural environment

Tooling

capabilities comparison matrix below to map Spring’s technology to that of Java EE

Capability Spring JavaEE Dependency Injection Spring Container CDI Transactions AOP / annotations EJB Web framework Spring Web MVC JSF AOP AspectJ (limited to Spring beans) Interceptors Messaging JMS JMS / CDI Data Access JDBC templates / other ORM / JPA JPA RESTful Web Services Spring Web MVC (3.0) JAX-RS Integration testing Spring Test framework Arquillian *

Interceptor classes and methods are defined using metadata annotations, or in the deployment descriptor of the application containing the interceptors and target classes

Interceptor Metadata Annotations

Interceptor classes must have a public, no-argument constructor

install the MevenIDE plugin

select all 7 plugins from the Maven category

Creating the Parent POM Project

create a parent pom project and then create ear, ejb and war child projects

create the EJB Project

make sure the Project Location is the root directory of the Parent POM Project

Maven recognise it as a sub-module

The WAR Project

The EAR Project

Deploying to GlassFish

There are a few ways of deploying applications to GlassFish

GlassFish command line utility to deploy to both local and remote servers is asadmin

Maven for the deployment

glassfish-v2/bin/asadmin

exec-maven-plugin

deploy