CodeOne 2018 – Day Four talks

Here are my notes from the talks I attended on Day Four at CodeOne (the successor toJavaOne). We have a summary report on our 4 highlights from Oracle CodeOne and  you can find Monday’s here, Tuesday’s here, and Wednesday’s here.

I have added my takeaways at the end of each. Any mistakes or omissions are mine. Please add comments if you would like any items expanded.

The Future of Java SE [DEV6323]

• Aim to be open, evolving, nimble, scalable
• Adding very easy, changing very hard (and removing)
• JDK9 first release to remove stuff.
• Recovered new release model for JDK and slippage in past
• All previous Oracle commercial features now in OpenJDK.
• java product management blog good source for minor differences between Oracle and OpenJDK
• jdk.java.net for openjdk binaries
• New release means late binding of features (old releases very ‘waterfall’ type releases). In new release late freeze date very close to GA date.
• 180 EA builds of j9, 45 EA builds in j10, 27 EA builds in j11
• Still same speed of dev but split across more releases.
• J12 has 4 JEPS so far
• New tools to manage change.
• jdeps in J8 to show class dependencies
• If you use libraries you inherit any mistakes, uses of unsafe, etc
• in j9, jpedrscan shows deprecated api elements -for-removal flag limits to ones which will be removed
• Incubator modules for non-final apis to get feedback from j9
• Features can be seen in OpenJDK projects and will appear when ready
• Portola – containers.
• Valhalla – performance/memory
• Panama – better JNI
• Loom – fibers for threading
• Amber – lang improvements 9dynamic class-file constants, raw string literals,switch statements
• Project Skara – move to git

My takeaways – If you want to see where Java is heading check out the projects. The new tools make updating much easier

Benefiting from Java 9 Improvements [DEV5372] 2005

• Full room for Venkat
• improvements/changes/additions
• Not covering modules as covered elsewhere
• interface now have private methods (can already have default and static). Cannot have private default. Should b used sparingly
• final in try with resources (finalise now deprecated in Java9. can implement AutoCloseable – added in J7 – in your code)
• In life and programming we seem to solve one se too programming only to create a new set of problems
• _ is internal symbol for “I don’t care” – used in Scala and Kotlin
• In j8 _ a warning and now error so can be used in later release for something.
• Stream – Java8 has limit and skip on stream but based on stream not valid values if you filter.Added takeWhile (like a break) and dropWhile (like Haskell).
• IntStream iterate makes it easy to replace for loops with increments other than 1 IntStream.iterate(0, i ->i <=15, i -> i + 3)
• Optional. Allows you to avoid null. Do not use as parameter for method. Optional unfortunately has get method which will throw error if no value. So avoid.  use result.orElse(default) – in java11 orElseThrow(). Java 9 adds ifPresentOrElse() .ifFirst can take stream

My takeaways – While jigsaw is exciting, there is lots of other cool stuff in Java9

JDK 9, 10, and 11: Pitfalls for the Unwary

• Show of hands – virtually all audience on j8
• If on 8 now, move to 11 not 9 or 10
• Compatibility very important
• minor issues 1.4 to 5 – assert became keyword and enum now reserved
• Deprecation added in 1.1
• In j8 492 deprecated API elements, none removed so far
• J9 start long overdue cleanup to remove stuff
• Clean code should work
• in j9 big change module system
• 75 modules in OpenjdK (27 javase and 48 jdk). 14 additional in Oracle (8 javaFX, 2 oracle specific)
• Most internal APIs now encapsulated (sun.misc.Unsafe) – used in common libraries so you may be using them.
• You can ignore modulesystem
• Module jar to module path – becomes automatic module
• upgrade code to proper module
• You can use –illegal-access permit|warn|debug\deny (big kill switch) to allow old style access and turn off encapsulation. Also –add-exports/–add-opens for more granular control. Add-exports can be added in jar manifest
• jdeps
• java.se.ee module not included by default in j9/10 (reactivation, corba, xml)
• accessed via –add-modules  All have standalone on Maven central. Can deploy on module or classpath
• _ is now a keyword (but __ okay for var name)
• Deleted 6 methods in j9 (mainly as issue with these in modularisation)
• new version strings now semantic versioning ie 1.8.0_131
• JNLP now strict parsing on config file
• ext directory now removed
• lots of GC options removed
• Logging changed in JVM (previously each had own)
• Lots of JVM flags removed
• 50 command flags no longer work and will stop JVM from starting if used

My takeaways – Documented key changes and ways to ease transition

Migrating Java UI Client Applications to OpenJDK 11 [DEV5990]

• Most desktop apps using J8. Recommended migration to j11
• Plugin, webstart, javafX not part of OpenJDK
• J7 first simultaneous release of OpenJDK and Oracle JDK
• most users still downloaded commercial releases and little OpenJDK testing as result
• Now converging means changes needed.
• Font rasterisation T2K >freetype
• lucida fonts removed in j11
• Anti-alias Ductus -> marlin
• JPEG classes gone (com.sun.jpeg.codec). Still java.imageio
• image processing Kodak >little cms. losing profiles for common colourspaces and replaced with Open source. But will give different results
• hiDpi support in windows. now scaled up to match. May need apps tweaking (ie Icon images scaled up)
• no javafX in j11 – needs downloading and adding
• Deployment technologies removed – plugin, webstart, appletviewer. Now need to be an application
• Plan to have packager in j12 to create bundles to run

My takeaways – lots of changes under the hood. Will need some planning to ensure not issue.

JUnit 5: The Next Step in Automated Testing for Java [DEV5916]

• Why change? (JUnit 4 released 2006)
• Goals;-
• Modernise (use J8)
• Modularise
• Extensible
• backwards compatible
• 3 major modules:-
• vintage (backward compatibility)
• Platform (test launch and tooling)
• Jupiter (new cool stuff)
• Demo to show backwards compatibility.
• JUnit5 replaces rules with extension model. @RuleMigrationSupport annotation needed in J5 if you still use
• assertAll make sit easy to run all tests
• @DisplayName and Emoji support
• Some language changes to clarify usage
• Extendwith Extension API
• Dependency Injection (ie for a mock)
• TestInfo object available
• @ValueSource allows easy definition
• Repeated tests
• Dynamic tests
• Test interfaces
• tests can be disables via OS, jdk version, custom logic
• parallel test execution
• Nested tests
• Assumptions
• ConsoleLauncher
• @billykorando

My takeaways – Great backwards compatibility but worth updating the tests to use new features

The Seven Deadly Sins of Software Development [DEV6081] [DEV5916]

• 1. No tests. Legacy code is code with no tests. Avoid the copy/paste design pattern
• 2. god objects. One huge class
• 3. comments. Delete commented out code. Comments should be safe,legal and rare.
• 4. dead code. kill it.
• 5. Driving without a seat belt. Antiviruses, locking down windows (shutup10), sandbox your browser, vpn and browsers
• 6. Not knowing tool you use. Learn to type as keyboard main input device. and have a decent keyboard. Then use keyboard shortcuts
• 7. bad names. being lazy.
• keepcalmandrefactor.com

My takeaways – great fun session to finish the show!