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SCBCD Study Notes
Chapter 1: EJB Overview
Please find the Study Notes and resources which covers the Chapter 1 : EJB Overview as part of the Sun Certified Business Component Developer exam CX-310-090.
- Identify the use, benefits, and characteristics of Enterprise JavaBeans technology, for version 2.0 of the EJB specification
- Identify EJB 2.0 container requirements,
- Identify correct and incorrect statements or examples about EJB programming restrictions.
- Match EJB roles with the corresponding description of the role's responsibilities, where the description may include deployment descriptor information.
- Given a list, identify which are requirements for an EJB-jar file.
Chapter 1 : EJB Overview Study Notes
1. Identify the use, benefits, and characteristics of Enterprise JavaBeans technology, for version 2.0 of the EJB specification.
Characteristics
Enterprise JavaBeans architecture is the standard component architecture for building distributed object-oriented business applications.
Enterprise JavaBeans architecture makes it possible to build distributed applications by combining components developed using tools from different vendors.
Application developers do not have to understand low-level transaction and state management details, multi-threading, connection pooling, and other complex low-level APIs.
Enterprise JavaBeans applications follow the Write Once, Run Anywhere™ philosophy of the Java programming language.
The Enterprise JavaBeans architecture addresses the development, deployment, and runtime aspects of an enterprise application’s life cycle.
Enterprise JavaBeans architecture defines the contracts that enable tools from multiple vendors to develop and deploy components
Enterprise JavaBeans architecture is compatible with the CORBA protocols. This allows remote invocations on session and entity beans from J2EE components that are deployed in products from different vendors.
Benefits
Defines the integration of EJB with the Java Message Service. Introduces message-driven beans (MDB) - a stateless components that are invoked by the container as a result of the arrival of a JMS message (MDB does not have home/home-local or remote/local interfaces).
Provides a local client view and support for efficient, lightweight access to enterprise beans from local clients.
Provides improved support for the persistence of entity beans.
Provides improved support for the management of relationships among entity beans (Local CMP Beans only).
Provides a query syntax (EJB QL) for entity bean finder and select methods (CMP only).
Provides support for additional methods in the home interface (business logic methods via ejbHome().
2. Identify EJB 2.0 container requirements
The EJB Provider can rely on the EJB 2.0 Container Provider to provide the following APIs:
Java 2 Platform, Standard Edition, v1.3 (J2SE) APIs
EJB 2.0 Standard Extension
JDBC 2.0 Standard Extension (support for row sets only)
JNDI 1.2 Standard Extension
JTA 1.0.1 Standard Extension (the UserTransaction interface only)
JMS 1.0.2 Standard Extension
JavaMail 1.1 Standard Extension (for sending mail only)
JAXP 1.0
3. Identify correct and incorrect statements or examples about EJB programming restrictions
An enterprise Bean must not use read/write static fields. Using read-only ( final) static fields is allowed.
An enterprise Bean must not use thread synchronization primitives to synchronize execution of multiple instances.
An enterprise Bean must not use the AWT functionality to attempt to output information to a display, or to input information from a keyboard.
An enterprise bean must not use the java.io package to attempt to access files and directories in the file system.
An enterprise bean must not attempt to listen on a socket, accept connections on a socket, or use a socket for multicast. Enterprise bean instance is allowed be a network socket client.
The enterprise bean must not attempt to use the Reflection API to access information that the security rules of the Java programming language make unavailable.
The enterprise bean must not attempt to create a class loader; obtain the current class loader; set the context class loader; set security manager; create a new security manager; stop the JVM; or change the input, output, and error streams.
The enterprise bean must not attempt to manage threads. The enterprise bean must not attempt to start, stop, suspend, or resume a thread; or to change a thread’s priority or name.
The enterprise bean must not attempt to directly read or write a file descriptor.
The enterprise bean must not attempt to obtain the security policy information for a particular code source.
The enterprise bean must not attempt to load a native library.
The enterprise bean must not attempt to gain access to packages and classes that the usual rules of the Java programming language make unavailable to the enterprise bean.
The enterprise bean must not attempt to define a class in a package.
The enterprise bean must not attempt to pass this as an argument or method result. The enterprise bean must pass the result of SessionContext.getEJBObject(), SessionContext.getEJBLocalObject(), EntityContext.getEJBObject(), or EntityContext.getEJBLocalObject() instead.
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