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The following is intended to outline our general product direction. It is intended
for information purposes only, and may not be incorporated into any contract.
It is not a commitment to deliver any material, code, or functionality, and should
not be relied upon in making purchasing decisions. The development, release,
and timing of any features or functionality described for Oracle’s products
remains at the sole discretion of Oracle.

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https://twitter.com/navalny/status/326243610418884610

4. Java: how to thrive
in the changing world
Alexey Fedorov, Ella Nekipelova
Oracle Engineers, JCK Team, Java Platform Group

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Agenda
 Bugs in your application
 Updating Java
 Java Platform Specification
 Compatibility: non-trivial example
 Summary

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Java application environment
JDK
Hardware
Frameworks
OS
Your Java
Application

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How to fix bugs
OS
JDK
Frameworks
App
Hardware
Create an issue or just fix it!
Create an issue. Opensource? Send a patch!
OracleJDK/OpenJDK: file a bug!
Create issue, wait for fix
Relax and enjoy 
Other vendors: it depends

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Updates
 Your Application
– Company and project update procedures
Frameworks
– Maven
 OS
– Install patches
– Upgrade/Change OS
 Hardware
– Replace one server box with another

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Updating Java
 Type of updates:
– Release update
 7u17 → 7u21
– Major platform update:
 Java 7 → Java 8
 Change Java vendor
– http://en.wikipedia.org/wiki/
List_of_Java_virtual_machines

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How do we manage changes?
OpenJDK / Oracle JDK
 JDK QA: tests for
 Public APIs (java.awt.*)
 Private APIs (sun.awt.*)
Community
 Java users around the world
Java from other vendors
Should be certified
 Java Compatibility Kit (JCK)
 Hundred thousands
conformance tests
 Feedback from licencees

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Problem
 Millions of Java application vs.
different versions and vendors
– How to agree?
Public specification play
role of the protocol!
API specification
(aka Javadoc)
Java
Language
Specification
(JLS)
Specification
Java Virtual Machine
Specification (JVMS)
Standalone
documents

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Java Specification is a protocol!
SMTP
 Hundreds of clients vs.
hundreds of servers
 100s + 100s = 100s
 Timeline
1982 – RFC 821
2001 – RFC 2821
2008 – RFC 5321
… and protocol cannot be changed too often
Java
 Millions of applications vs. dozens
releases from dozens vendors
 1000000s + 10s = 1000000s
 Timeline
1996 – JDK 1.0 2002 – J2SE 1.4
1997 – J2SE 1.1 2004 – J2SE 5.0
1998 – J2SE 1.2 2006 – Java SE 6
2000 – J2SE 1.3 2011 – Java SE 7

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Example: Adding null key to empty TreeMap

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How do we manage specification?
 Special procedures/policies
– Multiple review for every change
 Tracking
 Accepting / Rejecting
Special tools - http://jcp.org/en/resources/tdk
– Signatures
 SigTest - http://sigtest.java.net/
– Specification markup and conformance tests binding
 SpecTrac / SpecDiff

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Summary
 Updating the platform, which is used by hundreds millions
people around the world is a very difficult thing!
 Oracle has special tools, processes and policies
– Different policies for major releases (Java 7 → Java 8)
and for updates (7uXX)
– Tracking/Managing the Java Specification
 Special processes including multiple review
 Tools: SpecTrac, SigTest and others
Oracle takes care of you!

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Java: how to thrive in the changing world
Q&A
Alexey Fedorov (alexey.x.fedorov@oracle.com), @23derevo
Ella Nekipelova (ella.nekipelova@oracle.com)

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