J2EE Integration and Messaging

work in progress

Characteristic	Web Services	JMS	JCA
sync vs. async	sync	async
security/encryption	yes, WS-Security	yes
transactions	yes	yes	yes
reliability (guaranteed delivery)	yes	yes
batch
systems use same technology	java-non java	java-java	java-legacy/EIS

GoF Design Patterns

work in progress

Name	Description
Creational Patterns (AbFacBuildFacProSingle)
Abstract Factory	interface for creating family of related/dependent objects without specifying concrete classes
Builder	separates construction from representation; same construction process can create different objects
Factory Method	interface for creating an object; lets subclasses decide which class to instantiate
Prototype
Singleton	controls access to finite number of instances
Structural Patterns (AdBriComDecFaFlyProx)
Adapter	convert one interface to one the client expects
Bridge	functional abstraction -> internal implementation
Composite	hierarchical tree structures with elements of varying complexity but a uniform interface
Decorator	add or remove functionality without changing external appearance
Facade	unifying interface on top of a group of interfaces/components of a subsystem
Flyweight	sharing/reusing objects
Proxy	surrogate controls access to real object
Behavioral Patterns (ChainComIntItMedMemObStateStratTempVis or C2I2M2-OSS-TV)
Chain of Responsibility	message handled where it is first received or directed on to another object for handling
Command
Interpreter
Iterator	sequentially access items in a collection that is separate from the underlying collection
Mediator	object that manages message distribution among other objects
Memento	represents snapshot of object's state
Observer	broadcast messages to interested listeners
State	object alters behavior when internal state changes
Strategy	group of classes that represent a set of possible behaviors
Template Method
Visitor	think of using the enhanced for to iterate over a list in java and perform some operation on that list

underlined patterns are ones I have personally used

J2EE Persistence Strategies

This is a summary of the J2EE persistence strategies that a Sun Certified Enterprise Architect should be familiar with (use scrollbars at bottom to view entire table):

Strategy	Ease of Development	Performance	Scalability	Extensibility	Security	Strategy
CMP	relatively simple; preferred over BMP	container dependent	EJB container dependent *a	varies by implementation	EJB provided	CMP
BMP	more involved	very efficient w/control over SQL	EJB container dependent *a	varies by implementation	EJB provided	BMP
JDO	simple	possibly some performance penalty	developer managed	varies by implementation	developer managed	JDO
JPA	the simplest	possibly some performance penalty	EJB container dependent *a	varies by implementation	EJB provided	JPA
ORM/DAOs	simple	possibly some performance penalty	developer managed	varies by implementation	developer managed	ORM/DAOs
JDBC	most time-consuming and involved	theoretical best performance	developer managed	varies by implementation	developer managed	JDBC
iBatis/DAO	somewhere between ORM and JDBC	excellent performance	developer managed	varies by implementation	developer managed	iBatis/DAO

*a = stateless session beans more scalable than stateful

not covered by SCEA exam

Spring can help level the playing field outside EJB in some of the above developer managed areas by helping with transactioning, scalability and security.