Devoxx11: Jackpot 3.0 - Large Custom Refactorings

Jan Lahoda
Jackpot:

• originally from Sun labs
• uses the Abstract Syntax Tree (AST) --> knows java-language / syntax: smarter than simple regexp's
• ideal to refactor deprecated API's
• remove anti-patterns

Jackpot is now included in Netbeans 7.1

• use special 'Hint' syntax: Class.oldMethod => NewClass.newMethod ;;
• completely integrated in standard Netbeans hints / refactoring logic
  • hints are show in the IDE, directly to the developer
  • batch refactorings are allowed: completely integrated in the "Inspect and refactor" dialog (incl. managing hints)
  • run headless from the command line
• can be highly fine-tuned:
  • use instanceof checks
  • match on specific Java constructs: e.g. only look for Fields
  • check on target java version
  • combine multiple checks
  • write repeatable tests in ".test" file
• definitely worthwhile looking at for large refactorings of legace Java projects!

Devoxx11: Java 7 toolbox

Project coin brought some minor improvements to the Java language. Most notably:

• easier generics:
  • diamond operator <>: less copy/paste thanks to smarter compiler
  • less warnings on vararg's
• easier error-handling:
  • multicatch: less copy/paste
  • 'try-with-resource' contstruct: automatic & correct closing and error handling
• consistency / clarity
  • Strings in Switch
  • numbers improvements:
    • direct binary format: 0b0101001
    • logical grouping of large number in sub-chunks: 123_435_576L --> java ignores the underscores.

IDE support

• Netbeans & Intellij have excellent support for Java 7
  • inline hints and refactorings are offered
  • batch refactorings throughout the 'inspect and transform' dialog
• Eclipse is somewhat lagging behind.

Devoxx11: Android awesomeness

Chet Haase, Romain Guy and Philip Milne

Android 4.0: Tablet (3.0) & Phone (2.3) reunited

GridLayout: powerful & flexible lay-outing -- way too complex explanation.

Tools for profiling / debugging Android apps. "Experience matters"

• Memory
  • dumpsys: dump info of processes running on the device
    • adb shell dumpsys meminfocom.android.Launcher: dumps heap usage details
    • dumpsys gfxinfo: graphics chip
    • dumpsys window: decompose window objects used
  • DDMS: heap dump
  • jhat:
    • generate hprof
    • convert it with hprof-conv
    • in eclipse
    • check out "rootset references" for potentially memory leaks
  • MAT: Eclipse Allocation Tracker - http://eclipse.org/mat
• Performance
  • "use your eyes"
  • DDMS
  • track frames per second -> "trackFPS()" call in a PreDrawListener
• UI
  • 'crazy' stuff like high speed cams: Casio Ex-F1: replay the animation in slow motion
  • HierarchyViewer:
    • ViewTree
    • PixelPerfectTree
  • ViewServer

Devoxx11: Android Jumpstart

Lars Vogel

Excellent introduction to the Android development experience.

• tutorials on Android: www.vogella.de
• java --> class -- through dx-tool --> dex
• development environment: ADT for eclipse.
  • emulator: QEMU
  • DDMS: very powerful device debug mode
• API Components:
  • View for single views & ViewGroup for combining
  • Activity: app lifecycle - onPause() is the guaranteed last call to persist data
  • Intent: transitions to other apps
    • Implicit: Android decides
    • explicit: hard coded coupling to called app
  • Toast class: display quick temporary message
  • Preferences
  • DIY Views:
    • onDraw() method
    • Path class
    • selective invalidate() call to improve performance
  • ListActivity & ListAdapter
  • Threading & Async behaviour:
    • Threads: use runOnUiThread for async updates of the UI
    • Services
    • Broadcast & Receiver