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11 - 15 DECEMBER ANTWERP BELGIUM

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Java EE Enhancements for Real World Deployments

Nagesh SusarlaStaff Software EngineerBEA Systems


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Overall Presentation Goal

Get an understanding of the latest application packaging, upgrade and configuration features in a Java EE

environment

It covers in detail the application library features allowing Java EE EARs to become composite applications of reusable component libraries.


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Speaker’s Qualifications

Nagesh Susarla is a Staff Software Engineer at BEA SystemsNagesh Susarla leads the Java EE Application Container & WebApp teamNagesh Susarla has in the past worked on building the WebLogic Servlet and JSP containersNagesh Susarla writes frequently on WebLogic Server internals on dev2dev.bea.com


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Beyond the APIs …

Going beyond the Java EE programming APIs with features for packaging,

upgrading, and maintaining enterprise applications.


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Outline

Why Share? Application Libraries – What?

Production Redeployment Interruption-free?

Configuration ChangesCan it be external please?


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Outline

Why Share? Java EE Deployment UnitsCommon Libraries & PackagingJava EE Optional PackagesApplication Libraries Web Application Libraries

Production RedeploymentConfiguration Changes


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Java EE Deployment Units

EAR (Enterprise Archives)WAR (Web Application Archives)EJB (Enterprise Java Beans)RAR (Connector Archives)Application Clients


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Common Libraries

Common libraries are used by many applicationsDeveloped in-house Frameworks (Struts, Webwork, Spring, Portal)

Jar containing classes. EAR containing EJBsWebApp modules containing classes and

resources.


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Packaging Common Libraries

Package common modules: In the System Classpath. Within each application.

New versions require manually updating Application.Updating difficult when modules contain resources and classes.


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Problems

Scoping All Modules are tightly scoped. Modules cannot reference modules residing

outside an EARDelivering applications as a single EAR is limiting.


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Java EE Optional Packages

Share Plain Jars (w/ Classes) Any Module type can refer to an optional Jar.Via META-INF/MANIFEST.MF

Extension-List: optpack1 [optpackn] optpack1-Extension-Name: library-nameoptpack1-Specification-Version: (optional)optpack1-Implementation-Version: (optional)


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Java EE Optional Packages

Added to Module ClasspathMatch package with highest specification/implementation-versionDescriptors are ignored


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Application Libraries

GoalsSupported TypesSemanticsDeploymentReferencingPortability


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Application Libraries - Goals

Sharing of external code librariesPortability of library based applicationsOlder WebLogic Server ReleasesOther Application Servers

Require limited changes to existing applications to be packaged as a library.Provide Versioning Distribution and management.


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Application Libraries - Types

Referencing EAR

EAR Library

EJB jar

WAR library

Plain jar


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Application Libraries - Semantics

EJB jar A

WebApp BEJB Module

DAO Module

EAR EAR Library

References EJB Lib

DAO Module


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EJB jar A

WebApp BEJB Module

DAO Module

EAR EAR Library

EJB Lib

DAO Module


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EJB Module

DAO Module

EAR EAR Library

EJB Lib

DAO Module


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EJB Module

DAO Module

EAR Library

EJB Lib

DAO Module


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EAR Library

EJB Lib

DAO Module


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EAR Library

EJB jar A

WebApp B

EJB Lib (Lib)

DAO Module (Lib)

Merged View

EJB Lib

DAO Module


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Application(2) + Lib(2) => App’(4)Applications can reference: EAR Libraries: application.xml &

weblogic-application.xml mergedEJB jars: Included to the list to be

deployed.WARsPlain jars: Added to the App CP

Precedence order: App > Lib1 > Lib2 .


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Resource and ClassLoadingLibraries merged with referencing

application.No shared classloader for libraries

• Complicates redeployment of libraries and referencing applications.


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Application Library - Deployment

Package an EAR, EJB jar or WARAdd META-INF/MANIFEST.MF :Extension-Name: libNameSpecification-Version: 1.1Implementation-Version: 0.9

Multiple specification-versions may be deployed Deploy - Multiple libraries same specification-version but different implementation-version


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Application Libraries - Referencing

Add library-ref element to referencing EAR’s weblogic-application.xml.

library-ref

specification-version

library-name

implementation-version

exact-match

myLibrary

1.1

1.1.0

false


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Spec-version=1.1

exact-match=trueSpec-version=1.1

exact-match=false

Spec-version: 1.1

Impl-Version: 1.3

DAO Lib A

StableTeam App

PerpetualBeta App


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Spec-version=1.1

exact-match=trueSpec-version=1.1

exact-match=false

Spec-version: 1.1

Impl-Version: 1.3

Spec-version: 2.0

Impl-Version: 1.0

DAO Lib A DAO Lib A

StableTeam App

PerpetualBeta App


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Application Libraries – Portability

Goal: Deploy library based apps to older releases of WebLogic Server or to other application serversCommand line tool called “weblogic.appmerge”Uses the same code as the runtime Container.Physically merges the libraries with the application.Merges Descriptors and writes them to disk.


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Web Application Libraries

Similar to Application libraries WAR can refer to WAR libraries Useful in referring to web frameworksNested libraries are supportedweb.xml is merged. Filters, servlets from library visible to

referencing web app


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Web Application Libraries (cont’d)

Example: JSTL and JSF are shipped with WebLogic Server as WAR libraries.Semantics and Deployment are similar to Application Libraries.Resources and classes are returned giving precedence to the referencing WAR.


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Outline



Configuration ChangesCan it be external please?


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Production Redeployment

MotivationGoalsMultiple VersionsVersioned ArtifactsAutomatic RetirementTesting New Application VersionRollbackManaging Versions


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Production Redeployment

Challenge New development practices demand constant

updates to your applicationEnsure application availability during

application upgradeCurrent ApproachScheduled DowntimeRedundant cluster/domain with hardware

load-balancer


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Side by Side - Motivation

Load-balancer

Current Approach: Hardware-based LB WebLogic: Software-based Versioning

Primary Cluster

Redundant Cluster

Single Cluster / Server

App A

App A’

App A


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Side by Side Deployment - Goals

Allow multiple versions to coexistRetirement policy – Graceful, timeoutAbility to Test new version before opening it to the “world”Rollback to the previous versionManaging Versions


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Multiple versions

Version isolation of the same app (EAR or WAR)New Requests routed to active versionExisting client requests can finish up with

retiring versionUnshared local/app-scoped resourcesShared Global resourcesApplications recommended to be self-contained


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Versioned Artifacts

JNDIEach version has its own app-scoped JNDI

treeGlobal bindings are versioned

• Current version maintained in Work Context• Transparent lookup and bind/unbind/rebind

MBeansApplication and Runtime MBeansAppDeploymentMBean


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Automatic Retirement

Old version retired after new version is deployedPolicies:Graceful: wait for all in-flight work to be done

• In-Flight work: HTTP Sessions and Transactions• Can be preempted by undeploy

Timeout: Specify timeout period on redeploy


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Testing New App Version

Deploy new version in Admin-modeVersion Info in META-INF/MANIFEST.MF

Admin Mode:Accessible via Administration channel onlyWebApp Requests and JNDI lookups

Who can use Admin Mode? Members of the “AdminChannelUsers” group

Promote Admin-mode version to Active


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Rollback

Rollback to previous versionRedeploy previous versionPending retirement of previous version

Cancelled


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Managing Versions

Monitoring of all versions via WebLogic ConsoleStatus: admin-mode, active, retiring,

scheduled to be retired In-flight work: HTTP Sessions

Redeploy new versionsUndeploy retiring versions


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Outline



Configuration Changes


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Configuration Changes

MotivationWhat are Deployment PlansExampleTool Support


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Deployment Plans - Motivation


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Java EE 5 Deployment Descriptors optional.Annotations in source code.Configuration spread over descriptors/

annotationsEase of Development.Administrator?


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Java EE 5 Deployment Descriptors optional.Annotations in source code.Configuration spread over descriptors/

annotationsEase of Development.Administrator? Need a way to externally configure application environment.


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Deployment Plans - What

Optional xml file that resides outside the application.Set/Override environment property values.External resources (jndi-name)Tuning parameters (session-timeout, max-

cache)Cannot change non-configurable properties (ejb-name).Uses XPath to declare/override values.


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Deployment Plans


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Deployment Plans

Development


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Deployment Plans

Development

MyEjb.jar


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Deployment Plans

Development

MyEjb.jar

public class MyBean ... { @Resource DataSource mySqlDataSource;….


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Deployment Plans

Development

MyEjb.jar


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Deployment Plans

DevelopmentTesting

MyEjb.jar MyEjb.jar


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qaPlan.xml

Deployment Plans

DevelopmentTesting

MyEjb.jar MyEjb.jar


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qaPlan.xml

Deployment Plans

DevelopmentTesting

MyEjb.jar MyEjb.jar

<variable> <name>datasource</name> <value>QADataSource</value> </variable> ....


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qaPlan.xml

Deployment Plans

DevelopmentTesting

MyEjb.jar MyEjb.jar


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qaPlan.xml

Deployment Plans

DevelopmentTesting Staging

MyEjb.jar MyEjb.jar MyEjb.jar


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qaPlan.xml

Deployment Plans



ProductionPlan.xml


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qaPlan.xml

Deployment Plans



ProductionPlan.xml<variable> <name>datasource</name> <value>GADataSource</value> </variable> ....


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qaPlan.xml

Deployment Plans



ProductionPlan.xml


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Deployment Plans – Tool Support

Use weblogic.PlanGenerator for plan templates from an application.WebLogic Consoleweblogic.Deployer -plan


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Summary

Application Libraries aid modular development and maintenance of Real World ApplicationsDisruption free side-by-side deployments provide: Higher Quality of ServiceTest before exposing to the world

Deployment Plans let administrators alter configuration via external plans

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Q&A

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