Overview of new features in Java 7, including code examples, and suggested outline migration (upgrade) strategy.

1. New Features and
Migration Strategy
Neil Brown, 04/2013
- Brown Bag, Part 1 -

2. Java Standard Edition
(JSE) - Today

3. JSE, Today
● J6 end-of-life'd by Oracle 02-2013, but...
...there's life after J6:
● J7 mature - first GA (prod. ready) 07-2011
● J8 descoped (Jigsaw) and slipped (end
2012, 09-2013). Latest plan GA 03-2014

4. The Business Case

5. J7 - The Business Case
● Maintenance & security updates from Oracle
until at least 07-2014
● Performance improvements, translating to
better response times & throughput
○ HotSpot JVM enhancements
○ Improved concurrency support
● New features to keep dev team :-) and more
productive
○ Prerequisite / enabler for JEE7

6. New & Changed Features -
Highlights

7. J7 - Highlights
Targets improved performance & readability
● Java language enhancements (Project Coin)
● Concurrency enhancements (Fork/Join)
● New File I/O (NIO.2)
● XML APIs (JAXP, JAXB, JAX-WS) updated
● Platform (JVM) enhancements
○ HotSpot JVM performance improvements
○ Better support for dynamic lang. (invokedynamic)
○ New 'G1' garbage collector for certain server apps
...and more. See Oracle JDK 7 Adoption Guide

8. Migration -
How do we get there?

9. J7 - How do we get there?
In two phases:
1. Prove runtime compatibility & stability for
existing services on J7 runtime (JVM)
before...
2. Recompiling services to take advantage
of new language features; (at which point
we're committed to J7)

10. Phase 1 Migration Plan - Overview
1. Prove binary backwards compatibility
for JEE container & all Java services
○ Local dev. environment
○ Existing JEE container running on J7 JVM
○ Services deployed to J7+container
○ Unit and cursory integration tests pass
2. Prove behavioural compatibility for all
Java services
○ Install JDK 7 (JRE) in CI environment
○ Execute integration test suites

11. Phase 1 Migration Plan - Overview
3. Soak testing
● Prove reliability over extended period
4. Performance testing
● Confirm performance at least as good
5. Phased rollout J7 across remaining envs
● Upgrade JDK / JRE (still J6 javac only)
6. Prove in production
○ Services to run on J7 for agreed period before
declaring success and moving to phase 2 (J7 javac)

12. Phase 1 Migration Status 04/2013
1. Prove binary backwards compatibility for
JEE container & all Java services
○ Local dev. environment ................................ ✔
○ JEE container running on J7 JVM ............... ✔
○ Services deployed to J7+container .............. ✔
○ Unit and cursory integration tests pass ........ ✔
2. Prove behavioural compatibility for all
Java services
○ Install JDK 7 (JRE) in CI environment ........ ✍
○ Execute integration test suites .................... ✍

13. Language Enhancements
(Project Coin)

14. New Language Features
● Diamond operator
○ Type inference for generic types
● Multi-catch blocks
○ Improved exception handling
● Automatic resource management
○ aka try-with-resources
● Switch on strings
○ Enhanced switch statement
● Binary literals
○ Integer types expressed in binary

15. New Language Features
● Underscores in integer and binary literals
○ Increased code readability
Java 7 code examples
● https://bitbucket.org/neilbrown/java7-examples
Thanks for attending
Neil Brown