Spring AOP Part 1 - Custom Training Courses - Coreservlets.com

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Spring AOP Part 1 Originals of Slides and Source Code for Examples: http://courses.coreservlets.com/Course-Materials/spring.html Customized Java EE Training: http://courses.coreservlets.com/ Servlets, JSP, Struts, JSF/MyFaces/Facelets, Ajax, GWT, Spring, Hibernate/JPA, Java 5 & 6. Developed and taught by well-known author and developer. At public venues or onsite at your location.


For live Spring & Hibernate training, see courses att http://courses.coreservlets.com/. htt // l t / Taught by the experts that brought you this tutorial. Available at public venues, venues or customized versions can be held on-site at your organization. • Courses C d developed l d and d ttaught ht b by M Marty t H Hallll – Java 5, Java 6, intermediate/beginning servlets/JSP, advanced servlets/JSP, Struts, JSF, Ajax, GWT, custom mix of topics

• Courses developed and taught by EE coreservlets.com experts (edited by Marty) Customized Java Training: http://courses.coreservlets.com/ – Spring, Hibernate/JPA, EJB3, Ruby/Rails

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Topics p in This Section • • • •

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Aspect-oriented programming concepts Introduction Integration with Spring IoC Program integration using pointcuts

Java EE training: http://courses.coreservlets.com


Aspect-Oriented A tOi t d Programming Customized Java EE Training: http://courses.coreservlets.com/ Servlets, JSP, Struts, JSF/MyFaces/Facelets, Ajax, GWT, Spring, Hibernate/JPA, Java 5 & 6. Developed and taught by well-known author and developer. At public venues or onsite at your location.

Aspect-Oriented p Programming g g • Addresses broad application responsibilities – Logging – Transaction i management – Error management

• Modularizes M d l i responsibility ibilit – e.g., logging – The encapsulation of a responsibility is an advice element

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Aspect-Oriented p Programming g g • Identifies program facets – Uses mechanisms beyond traditional OO models • e.g., All POJO getter methods from com.company.persistence p y p package p g class members

– Target execution point is the join point • e.g., constructor or method invocation

–P Program component li linking ki the h execution i target is i a pointcut

• Applies advisor to program facets – An aspect is a single unit associating and applying an advice to p pointcuts 7


Spring p g AOP • Programming model – Method-only interceptors

• Advisor – Captures advice behavior using plain POJOs – AspectJ APIs • A Annotations t ti and d library lib API APIs • Advice beans are well-formed – Conform to method conventions but not special interfaces

– AOP Alliance APIs • Advice beans implement interfaces

– Spring AOP XML schema advice types 8


Spring p g AOP Continued • Pointcut – AspectJ API annotations mapped to bean methods – Spring AOP XML schema pointcut declarations

• Aspect – AspectJ advice with advice and pointcut definitions using i AspectJ A tJ annotations t ti – Spring AOP XML schema aspect declarations

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General Spring IoC Customized Java EE Training: http://courses.coreservlets.com/ Servlets, JSP, Struts, JSF/MyFaces/Facelets, Ajax, GWT, Spring, Hibernate/JPA, Java 5 & 6. Developed and taught by well-known author and developer. At public venues or onsite at your location.

Spring p g IoC Process •

Develop POJO library – coreservlets coreservlets.Customer Customer, coreservlets.CustomerQuery coreservlets CustomerQuery, coreservlets.MockCustomerQuery

•

Register Spring JARs

•

Create the bean definitions file

– spring-core.jar, spring-context.jar , spring-beans.jar , commons-logging.jar – classpath:/coreservletsContext.xml

•

Register beans –

•

Inject dependencies –

•

Initialize the container – BeanFactory beanFactory = new ClassPathXmlApplicationContext( new String[]{"classpath:/ coreservletsContext.xml"});

•

Access and use beans – CustomerQuery customerQuery = (CustomerQuery) beanFactory.getBean("customerQuery"); Java EE training: http://courses.coreservlets.com

Develop p POJO Library y public class Customer { private String id; private String name; public Customer(String id, String name){ this.id = id; this.name = name; } public String getId() { return id; } public String getName() { return name; } }


Develop p POJO Library y public interface CustomerQuery { public Customer getCustomerByName(String name); }


Develop p POJO Library y public class MockCustomerQuery implements CustomerQuery { private List customers; public MockCustomerQuery(Listcustomers) { this.customers = customers; } public Customer getCustomerByName(String name) { for(Customer c : customers){ if(c.getName().equals(name)){ return c; } } return null; } } Java EE training: http://courses.coreservlets.com

Create Bean Definitions • Location – classpath:/coreservletsContext.xml


Register Beans and Interdependencies /b Java EE training: http://courses.coreservlets.com

Access and Use Beans import org.springframework.context.support.*; public class Main { public static void main(String[]args) { BeanFactory beanFactory = new ClassPathXmlApplicationContext( "/coreservletsContext.xml"); CustomerQuery query = (CustomerQuery) beanFactory.getBean("customerQuery"); Customer customer = query.getCustomerByName("Java Joe"); System.out.println(customer); } }

Standard output

Customer id=jjoe, name=Java Joe Java EE training: http://courses.coreservlets.com


Spring S i AOP Hello World Customized Java EE Training: http://courses.coreservlets.com/ Servlets, JSP, Struts, JSF/MyFaces/Facelets, Ajax, GWT, Spring, Hibernate/JPA, Java 5 & 6. Developed and taught by well-known author and developer. At public venues or onsite at your location.

Spring p g AOP JARs • • • •

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spring-aop.jar aopalliance.jar p j j aspectjweaver.jar cglib.jar


Spring AOP Hello World Process • Identify concern • Select S l t join j i points i t – All methods exposed by coreservlets.CustomerQuery

• Create advice – e.g., implement org.aopalliance.intercept.MethodInterceptor

• Create AOP definitions file – Create file classpath:/coreservletsAopContext.xml – Register spring-aop NS

• Register advice beans –

• Create pointcut definitions – Identifty join points – p g p p p g

• Define aspects – 20


Select Join Points • All persistence methods – coreservlets.CustomerQuery method

implementations public interface CustomerQuery { public Customer getCustomerByName(String name); }

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Select Join Points public class MockCustomerQuery implements CustomerQuery { private List customers; public MockCustomerQuery(Listcustomers) { this.customers = customers; } public Customer getCustomerByName(String name) { for(Customer c : customers){ if(c.getName().equals(name)){ return c; } } return null; } } 22


Create Advice import org.aopalliance.intercept.MethodInterceptor; import org.aopalliance.intercept.MethodInvocation; import coreservlets.Customer; public class HelloWorldAdvice implements MethodInterceptor { public Object invoke(MethodInvocation invocation) throws Throwable { return new Customer(){ public String toString(){ return "Hello World!"; } }; } } 23


Create AOP Definitions File • Location – classpath:/coreservletsAopContext.xml


Register g Advice Beans

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Create Pointcut Definitions /b

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Define Aspects p / 27


Domain Beans /b Java EE training: http://courses.coreservlets.com

Initialize Spring p g IoC Container import org.springframework.context.support.*; public class Main { public static void main(String[]args) { BeanFactory beanFactory = new ClassPathXmlApplicationContext( "/coreservletsContext.xml", "/coreservletsAopContext /coreservletsAopContext.xml xml"); ); ... } }


Access and Use Beans Without Spring AOP import org.springframework.context.support.*; public class Main { public static void main(String[]args) { BeanFactory beanFactory = new ClassPathXmlApplicationContext(new String[]{ "/coreservletsContext.xml"});

Omitted classpath:/coreservletsAopContext.xml

CustomerQuery query = (CustomerQuery) beanFactory beanFactory.getBean( getBean("customerQuery"); customerQuery ); Customer customer = query.getCustomerByName("Java Joe"); System.out.println(customer); } } Standard output

Customer id=jjoe, name=Java Joe Java EE training: http://courses.coreservlets.com

Access and Use Beans With Spring AOP import org.springframework.context.support.*; public class Main { public static void main(String[]args) { BeanFactory beanFactory = new ClassPathXmlApplicationContext(new String[]{ "/coreservletsContext.xml", "/coreservletsAopContext.xml"}); CustomerQuery query = (CustomerQuery) beanFactory.getBean("customerQuery"); Customer customer = query.getCustomerByName("Java Joe"); System.out.println(customer); } }

Output overridden by bean advisor Standard output

Hello World! Java EE training: http://courses.coreservlets.com


IIntegrated t t d Process P Spring IoC and AOP Customized Java EE Training: http://courses.coreservlets.com/ Servlets, JSP, Struts, JSF/MyFaces/Facelets, Ajax, GWT, Spring, Hibernate/JPA, Java 5 & 6. Developed and taught by well-known author and developer. At public venues or onsite at your location.

Integrated Process Spring IoC and AOP, AOP Step 1 • Develop POJO library – e.g., coreservlets.Customer, coreservlets.CustomerQuery, coreservlets.MockCustomerQuery

• Register Spring IoC and AOP JARs – spring-core.jar, spring-context.jar, spring-beans.jar, spring-aop.jar, aopalliance.jar, p j , aspectjweaver.jar, p j j , cglib.jar, g j , commons-logging.jar gg g j

• Create the bean definitions file – e.g., classpath:/coreservletsContext.xml

• Register R i t b beans – e.g.,

• Inject dependencies – e.g., – e.g., Java EE training: http://courses.coreservlets.com

Integrated Process Spring IoC and AOP, AOP Step 2 • Identify concern • Select S l t join j i points i t – All methods exposed by coreservlets.CustomerQuery




• Create pointcut definitions – Identifty join points – p g p p p g



Integrated Process Spring IoC and AOP, AOP Step 3 • Initialize the container – Specify both domain bean and Spring AOP definitions paths – e.g., BeanFactory beanFactory = new ClassPathXmlApplicationContext( new String[]{ "classpath:/coreservletsContext.xml", "classpath:/coreservletsAopContext.xml"});

• Access and use beans – e.g., CustomerQuery customerQuery = (CustomerQuery) beanFactory.getBean("customerQuery");

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Addressing Add i the th Application Customized Java EE Training: http://courses.coreservlets.com/ Servlets, JSP, Struts, JSF/MyFaces/Facelets, Ajax, GWT, Spring, Hibernate/JPA, Java 5 & 6. Developed and taught by well-known author and developer. At public venues or onsite at your location.

Pointcuts • Join point – Identifies a program execution point

• Pointcut – Identifies a set of join points such as all persistence methods – Defined by using general specifications about a class system • Enclosing class – – – –

Supertype S t Modifier Name Package namespace

• Method – Name – Return type – Argument types 37


Pointcut Definition (PCD) ( ) • Keywords – execution • Method signature matching expression • Matching includes supertypes

– within • Package and class name matching expression g does not include supertypes p yp • Matching

– this • Class or supertype matching expression proxy y bean • Matches on the p

– target • Class or supertype matching expression • Matches on the actual bean

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Pointcut Definition (PCD) ( ) • Keywords continued – args • Method parameter matching expression • Includes runtime supertypes • Refines R fi when h combined bi d with ith another th PCD PCD; e.g. target t t • Also maps join point parameters to advice bean parameters

– beans • Bean B identfier id tfi pattern tt matching t hi expression i

• Operators – Combines expression combinations using logical operators: AND, OR,

NOT • Context – @org.aspectj.lang.annotation.Pointcut g p j g content – Spring AOP XML expression attribute value • 39



Execution PCD Customized Java EE Training: http://courses.coreservlets.com/ Servlets, JSP, Struts, JSF/MyFaces/Facelets, Ajax, GWT, Spring, Hibernate/JPA, Java 5 & 6. Developed and taught by well-known author and developer. At public venues or onsite at your location.

Execution PCD Details • PCD Expression – execution(* *. g expression>) p (>> p public j java.lang.String g g coreservlets.Customer.getName(). g args=[]. exit=return[Java Joe] >>> public java.lang.String coreservlets.Customer.toString(). args=[]. exit=return[Customer id=jjoe, name=Java Joe] >>> public abstract coreservlets.Customer coreservlets.CustomerQuery.getCustomerByName(java.lang.String). args=[Java Joe]. exit=return[Customer id=jjoe, name=Java Joe] Java EE training: http://courses.coreservlets.com

Execution PCD Match Origins g >>> public java.lang.String coreservlets.Customer.getName(). args=[]. exit=return[Java Joe] >>> public java.lang.String coreservlets.Customer.toString(). args=[]. exit=return[Customer id=jjoe, name=Java Joe] >>> public abstract coreservlets.Customer coreservlets.CustomerQuery.getCustomerByName(java.lang.String). args=[Java Joe]. exit=return[Customer id=jjoe, name=Java Joe]

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public class MockCustomerQuery p Q y implements p CustomerQuery Q y { ... public Customer getCustomerByName(String name) { for(Customer customer : customers){ if(customer.getName().equals(name)){ return customer; execution(* *(..)) } } return null; } } Java EE training: http://courses.coreservlets.com


public class SummarizingMethodAdvice public Object invoke(MethodInvocation inv) throws Throwable { execution(* *(..)) ... Object returnValue = inv.proceed(); b ff buffer += " ". exit=return[" it t [" + returnValue t V l + "]"; "]" ... } 60



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public class Main { public static void main(String[]args) { BeanFactory beanFactory = new ClassPathXmlApplicationContext(new String[]{ "/coreservletsContext.xml", execution(* *(..)) "/coreservletsAopContext.xml"}); CustomerQuery query = (C t (CustomerQuery) Q ) b beanFactory.getBean("customerQuery"); F t tB (" t Q ") Customer customer = query.getCustomerByName("Java Joe"); } Java EE training: http://courses.coreservlets.com }

More Execution PCD Examples p • Drop access modifier –

• A Any access modifier, difi return t type t and d coreservlets l t package

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–


More Execution PCD Examples Continued • Any access modifier, return type, package, class, and method name –

• Any A public bli bean b property t getter tt method th d –

• Any A public bli bean b property setter method h d –

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Within PCD Customized Java EE Training: http://courses.coreservlets.com/ Servlets, JSP, Struts, JSF/MyFaces/Facelets, Ajax, GWT, Spring, Hibernate/JPA, Java 5 & 6. Developed and taught by well-known author and developer. At public venues or onsite at your location.

Within PCD Details • PCD Expression – within()

• Expression elements – Enclosing package and class name pattern

• Expression E i example l – within(coreservlets.MockCustomerQuery)

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Within PCD Guidelines • Match target – Matches on the instantiated/concrete bean type – Does not match on target bean supertypes • e.g., g coreservlets.CustomerQuery will not match on an instantiation of coreservlets.MockCustomerQuery

– Does not match on method signature elements

• Pattern – Expression supports partial or full replacement using wildcard(s)

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Integrated Process Spring IoC and AOP, AOP Step 1 • Develop POJO library – e.g., coreservlets.Customer, coreservlets.CustomerQuery, coreservlets.MockCustomerQuery

• Register Spring IoC and AOP JARs – spring-core.jar, spring-context.jar, spring-beans.jar, spring-aop.jar, aopalliance.jar, p j , aspectjweaver.jar, p j j , cglib.jar, g j , commons-logging.jar gg g j

• Create the bean definitions file – e.g., classpath:/coreservletsContext.xml

• Register R i t b beans – e.g.,

• Inject dependencies – e.g., – e.g., Java EE training: http://courses.coreservlets.com

Integrated Process Spring IoC and AOP, AOP Step 2 • Identify concern • Select S l t join j i points i t – All methods exposed by coreservlets.CustomerQuery




• Create pointcut definitions – Identifty join points – p p g



Integrated Process Spring IoC and AOP, AOP Step 3 • Initialize the container – Specify both domain bean and Spring AOP definitions paths – e.g., BeanFactory beanFactory = new ClassPathXmlApplicationContext( new String[]{ "classpath:/coreservletsContext.xml", "classpath:/coreservletsAopContext.xml"});

• Access and use beans – e.g., CustomerQuery customerQuery = (CustomerQuery) beanFactory.getBean("customerQuery");

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Execution PCD Process Step 1 Highlights • classpath:/coreservletsContext.xml


Select Join Points • General coreservlets library methods – coreservlets package members • All class member methods – expression="within(coreservlets.*)" e p ess o t (co ese ets. )

coreservlets.Customer coreservlets.CustomerQuery coreservlets.MockCustomerQuery coreservlets.jdbc.JdbcCustomerQuery

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Create Advice import org.aopalliance.intercept.* public class SummarizingMethodAdvice implements MethodInterceptor { public Object invoke(MethodInvocation inv) throws Throwable { ... return inv.proceed(); ... } }

72


Create Advice Continued public Object invoke(MethodInvocation inv) throws Throwable { String buffer = inv.getMethod().toGenericString() + ". args=" + Arrays.toString(inv.getArguments()); try{ Object returnValue = inv.proceed(); buffer += ". exit=return[" + returnValue + "]"; return returnValue; } catch(Throwable t){ buffer += " - exit=error[" + t + "]"; throw t; } finally{ Logger log = Logger.getLogger(inv.getThis().getClass()); log.debug(">>>" + buffer); } } 73




Register g Advisor Beans

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Define Pointcuts

Execution PCD expression

Package namespace

PCD expression keyword

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Class wildcard Does not match on sub-packages


Define Aspects p

Pointcut reference

Advisor reference

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Initialize Spring p g IoC Container import org.springframework.context.support.*; public class Main { public static void main(String[]args) { BeanFactory beanFactory = new ClassPathXmlApplicationContext( "/coreservletsContext.xml", "/coreservletsAopContext /coreservletsAopContext.xml xml"); ); ... } }


Access and Use Beans import org.springframework.context.support.*; public class Main { public static void main(String[]args) { BeanFactory beanFactory = new ClassPathXmlApplicationContext(new String[]{ "/coreservletsContext.xml", "/coreservletsAopContext.xml"}); CustomerQuery query = (CustomerQuery) beanFactory beanFactory.getBean( getBean("customerQuery"); customerQuery ); Customer customer = query.getCustomerByName("Java Joe"); } Standard output } >>> p public j java.lang.String g g coreservlets.Customer.getName(). g args=[]. exit=return[Java Joe] >>> public java.lang.String coreservlets.Customer.toString(). args=[]. exit=return[Customer id=jjoe, name=Java Joe] >>> public abstract coreservlets.Customer coreservlets.CustomerQuery.getCustomerByName(java.lang.String). args=[Java Joe]. exit=return[Customer id=jjoe, name=Java Joe] Java EE training: http://courses.coreservlets.com

More Within PCD Examples p • Fully-qualified classname – Configuration C fi ti is i bound b d to t the th implementation i l t ti type t

• Interface-type Interface t pe – Quietly fails to match i " ithi ( l t M kC t Q )"/

• Interface-type – Name must be within the coreservlets package and include the term C t CustomerQuery Q

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More Within PCD Examples p • General package name pattern – Matches only onl on the immediate members of the coreservlets c s l ts package

• All methods from all classes of all packages – What's the point?

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Target PCD Customized Java EE Training: http://courses.coreservlets.com/ Servlets, JSP, Struts, JSF/MyFaces/Facelets, Ajax, GWT, Spring, Hibernate/JPA, Java 5 & 6. Developed and taught by well-known author and developer. At public venues or onsite at your location.

Target g PCD Details • PCD Expression – target()

• Expression elements – Enclosing package and class name pattern

• Expression E i example l – target(coreservlets.CustomerQuery)

• Match target – Matches on the instantiated/concrete bean type – Matches on target bean supertypes – Does not match on method signature elements

• Pattern support – NONE – Wildcards will generate errors

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Target g PCD Guidelines • Assists – POJOs POJO hhaving i well-defined ll d fi d interface i t f types t – Many concrete POJOs implementing marker interfaces

• Hinders – Concrete types sharing no general interfaces

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Execution PCD Process Step 1 Highlights • classpath:/coreservletsContext.xml


Select Join Points • General coreservlets.CustomerQuery i implementors l t and d methods th d package coreservlets; public interface CustomerQuery { public i Customer getCustomerByName(String i name); }

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Create Advice import org.aopalliance.intercept.* public class SummarizingMethodAdvice implements MethodInterceptor { public Object invoke(MethodInvocation inv) throws Throwable { ... return inv.proceed(); ... } }

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Create Advice Continued public Object invoke(MethodInvocation inv) throws Throwable { String buffer = inv.getMethod().toGenericString() + ". args=" + Arrays.toString(inv.getArguments()); try{ Object returnValue = inv.proceed(); buffer += ". exit=return[" + returnValue + "]"; return returnValue; } catch(Throwable t){ buffer += " - exit=error[" + t + "]"; throw t; } finally{ Logger log = Logger.getLogger(inv.getThis().getClass()); log.debug(">>>" + buffer); } } 88




Define Pointcuts

Execution PCD expression

PCD expression p keyword y

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Fully-qualified yq interface type yp


Define Aspects p

Pointcut reference

Advisor reference

>> [MockCustomerQuery] public abstract coreservlets coreservlets.Customer Customer coreservlets.CustomerQuery.getCustomerByName(java.lang.String). args=[Java Joe]. exit=return[Customer id=jjoe, name=Java Joe] Java EE training: http://courses.coreservlets.com

More Target g PCD Examples p • Concrete type – Configuration C fi ti is i bound b d to t a particular ti l concrete t type t

• Supertype S pert pe ma may be an interface or class

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Wrap-up Customized Java EE Training: http://courses.coreservlets.com/ Servlets, JSP, Struts, JSF/MyFaces/Facelets, Ajax, GWT, Spring, Hibernate/JPA, Java 5 & 6. Developed and taught by well-known author and developer. At public venues or onsite at your location.

Summary y • Manage AOP code and definitions separately • Identify concerns and join points • Create advice – e.g., implement org.aopalliance.intercept.MethodInterceptor

• Create C t AOP d definitions fi iti file fil – Create file classpath:/coreservletsAopContext.xml – Register spring-aop NS


• Create p pointcut definitions – Identifty join points –

• Define aspects p – 96

• Merge AOP code and definitions with domain products at runtime Java EE training: http://courses.coreservlets.com


Q Questions? ti ? Customized Java EE Training: http://courses.coreservlets.com/ Servlets, JSP, Struts, JSF/MyFaces/Facelets, Ajax, GWT, Spring, Hibernate/JPA, Java 5 & 6. Developed and taught by well-known author and developer. At public venues or onsite at your location.