JRebel traning at eXo

1. Zero redeployment with JRebel
Minh Hoang TO
Portal Team

2. Agenda
1. JRebel
2. GateIn zero-redeployment
3. How does JRebel work?
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3. JRebel
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4. - Developer(s): Zero Turnaround
- Written in: Java
- License: Proprietary
- Highlighted features:
Immediately visible code changes without redeploying
Easy installation and simple configuration
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5. Free license plans
OSS plan
Commiters of Open Source projects have access to free license
Social plan
Free license in exchange of privileged to post on Twitter/Facebook account
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6. GateIn zero-deployment
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7. GateIn code changes in IDE are reflected immediately on browser without the
need of redeploying. Say GOODBYE to tedious redeploy work
Productive dev environment applicable to any eXo product:
Social, Wiki, Forum, ECMS, Platform
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8. Demo
- Targeted Maven artifacts:
exo.portal.webui.portal (basic UI components of GateIn portal)
exo.portlet.exoadmin (core portlets of GateIn)
- Expectation:
Code changes on portal/portlet components from those two artifacts take
effect on browser without the need of redeploying .war to Tomcat
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9. Before demo
1. Customize packaging/tomcat/pkg/src/main/resources/tomcat/bin/gatein-dev.sh
2. Generate rebel.xml in targeted Maven artifacts
3. Build and run GateIn
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10. rebel.xml
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11. rebel.xml
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12. JRebel agent starts
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13. Demo starting ...
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14. How does JRebel work?
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15. Object & Class
MyObject obj = new MyObject();
Class<?> type = obj.getClass();
1. Behavior of method call on 'obj' is determined by 'type'
2. 'type' is identified by MyObject.class bytecode and context ClassLoader of the
code MyObject obj = new MyObject();
3. Once loaded, 'type' could not be unloaded or changed (class loader holds a
vector of loaded classes)
4. JRebel approach to redefine 'type'
Black box as JRebel is not open source! But described as a combination of
Instrumentation API + Byte code handling + Class loader
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16. Class redefinition
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17. MANIFEST.MF
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18. JRebel agent
The code in AgentInstall is likely to be
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