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@theNeomatrix369
Are you pairing with tools to improve code quality ?
Leaning on tools & techniques to improve code quality
@theNeomatrix369
About meMani (@theNeomatrix369)
● LJC Associate● Adopt OpenJDK and JSR (JCP Member)● blog: http://neomatrix369.wordpress.com● github: http://github.com/neomatrix369● bitbucket: https://bitbucket.org/neomatrix369
Avatar: courtesy of Recworks: Dan Smallman @dsrecworks
@theNeomatrix369
- I’m only sharing my learning experience - YMMV !- Experimental yet practical methods- Learning via validating and verifying- A silver bullet to solve all problems- One shirt fits all solution- Not about any specific product
Disclaimer
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Agenda- How it all started for me...- First steps to learning to use these tools...- Inventions- Observations- Introspection- Discoveries- Conclusion
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How it all started for me...
@theNeomatrix369
My first computer - 8088 processor (8-bit processor)
My first game - Digger (not PacMan)
Mid-1990s
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Between 2000-2010
Career started as a hobby - years later become a profession
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Early 2010
Desire…more knowledge,
experience & skills
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Communities...met dev. communities in London and other parts of Europe!
LSCC
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Sowing of seeds...
@theNeomatrix369Source: SonarQube (aka Sonar)
What does code quality mean to you ?
Is it the seven axes of quality ?
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How do we improve quality ?
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Pair programming is good...
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...but not always available...
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Then I had an idea...
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Why not use tools...
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First steps to learning to use these tools...
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Treemaps are awesome...
10,000 feet view !
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Dashboard - my own Quality metrics
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Issue violations & Duplications
Checkstyle, Findbugs, PMD rules
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What is Cyclomatic Complexity
or Complexity ?
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In simple words, it is thenumber of pathways
due to decision logic in a software program.
See Wikipedia definition
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ComplexitySee Definitions glossary
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Refactoring saves the day...Higher complexity (CCI: 4) void doSomethingBasedOnCurrentState( int state ) {
switch ( state ) {
case INACTIVE: //doSomethingForInActiveState(); break;
case ACTIVE: //doSomethingForActiveState(); break;
case UNKNOWN: //doSomethingForUnknownState(); break;
}
}Lower complexity (CCI: 1)
public enum CurrentState { INACTIVE { void doSomething() {} }, ACTIVE { void doSomething() {} }, UNKNOWN { void doSomething() {} };
abstract void doSomething();}
CCI Source: SonarQube (Complexity scores)
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Refactoring resources...
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Test coverage - unit & integration tests
Hint: EclEmma, JaCoCo and IntelliJ Code Coverage
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Performance tuning tools (short and long feedback loops)
- Application behaviour- GC behaviour (on the JVM)- Early or late feedback (during development, or post- development)- Profiling
Some known tools: Java Mission Control, Java Flight Recorder, jconsole, GC Viewer, VisualVM, HeapAnalyzer, PerfAnal, JAMon, HPJMeter, HonestProfiler, mjProf, Eclipse Memory Analyzer (MAT)
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Performance tuning tools(short feedback loop)
Profiling tools
- Honest profiler- mjProf- Eclipse Memory Analyzer (MAT)- others
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Performance tuning tools(short feedback loop)
JITWatch* - @chriswhocodes
Understand...Java HotSpot Just-In-Time (JIT) compiler...program execution.
Hot Method too big - among other JIT optimisation errors
Java 7 and Java 8 core methods above the default hot method inlining threshold
*an Adopt OpenJDK F/OSS project
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Performance tuning tools(long feedback loop)
Censum - jclarity.com
- GC Analysis, similar to GC Viewer- Additional metrics and graphs- Built-in analytics, recommendations & heuristics
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The others... Google CodePro
Coverity ThreadSafe
IntelliJ IDEA Squale
Veracode
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Collaborate...share, crowd-source, machine learning...
(Hippie completion)
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Inventions...
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Strategies (checklists)
[ ] Strategy (method in the madness)[ ] Strategy (interesting, ear-marked)
Find the checklists in the Resources section at the bottom
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Continuous Inspection
Individual inspections
(local first)
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Continuous Inspection (local first)
Some more individual inspections
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Rule of thumbMetrics Rule Mitigating action
Method complexity >= 6 pathways Refactor: split method
Class complexity >= 60 pathways Refactor: split class
LCOM4 >=2 responsibilities Refactor: new class / subclass
RFC per class > 40 connections (both ways - afferent & efferent)
Refactor: reduce dependencies and dependents, split class
Source: SonarSource resource, Book: SonarQube in Action
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Observations...
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Repetition...helps build muscle memory
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Katas - individual partsissues violations
duplicationscode (test) coverage
mutation testingquickcheck
immutability checkcomplexity check
performance check
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Introspection...
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Trust but verify
Trust your tool(s)……believe in your method(s)
Adopt advice from peers & experts… ...but also evaluate it yourself
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Do these factors make up quality ?
developer: knowledge and skillsx
tool: tunability, features & capabilitiesx
(environment & team)
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(when you take a plunge)
...its not just about tools, there is more….
Discovery…
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Discovery…
...firstly a tool is onlya temporary scaffolding…
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Discovery…
...its about methods and techniques...
(because tools are only a dumb conduit)
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Discovery…
(...if you dive deeper…)its about the practise and developing good habits
"I'm not a great programmer; I'm just a good programmer with great habits.” Kent Beck, http://en.wikiquote.org/wiki/Kent_Beck
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Realisations...
Writing good quality code takes practice, effort and time
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Quality is a concerted effort of not just a single developer but a team of developers !
Realisations...
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- Repetition- Measuring progress- Early detection- Short feedback loop- Reliable pairing - Filling the (missing) gap- Powerful & effective ally
Conclusion
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Summary
● Personal story● Various methods & techniques: processes● Strategies (checklists)● Inventions & observations: continuous inspection (local first) & katas ● Discoveries and Realisations ● (My) conclusion
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Gratitude - big thanks !...to the dev communities of London and Europe!
LSCC
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Q & A
Keep them coming !
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Its time to share your methods and help improve our craft !
Please tweet your feedback at @theNeomatrix369
@theNeomatrix369
Devoxx UK - 17-19th June 2015
Socrates UK - 4-7th June 2015
Conferences
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Let’s change the Java ecosystem, together!
Daniel Bryant @danielbryantuk Mani Sarkar @theNeomatrix369
With support from the JCP, London Java Community and Java communities worldwide
@adoptajsr@adoptopenjdk
[email protected]@openjdk.java.net
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Resources● SonarQube resources● SonarQube Nemo project● Discussions on Sonar on JavaRanche● Installing SonarQube (formerly Sonar) on MacOsX Mountain Lion● Using SonarQube on MacOsX Mountain Lion● SonarGraph (http://www.hello2morrow.com/products/sonargraph)● Jitwatch: http://github.com/AdoptOpenJDK/jitwatch● QuickCheck (https://bitbucket.org/blob79/quickcheck)● Mutation Testing (http://pitest.org/ or http://ortask.com/mutator/)● Mutability Detector (https://github.com/MutabilityDetector/)● AssertJ - fluent assertions for Java (plus other fluent libraries)● Censum (@jclarity product - see http://www.jclarity.com/censum/)● Profilers: HonestProfiler, mjProf, Eclipse Memory Analyzer (MAT)● Books: Sonar in Action (http://www.manning.com/papapetrou/), Software
Craftsmanship by Sandro Mancuso, Uncle Bob’s Clean Code
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Predecessor to this presentation...
http://bit.ly/1lk8NDW
to improve code quality !
SonarQubetm
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Strategy (method in the madness)
[ ] Unit & Integration test coverage: EclEmma, JaCoco, IntelliJ Code Coverage check[ ] Most violated rules (Blockers, Critical, Major, Minor violations)[ ] Duplication removal - DRY[ ] Complexity (package-, file/class-, method-levels)[ ] Performance: profiling (memory, cpu, hardware)[ ] Performance: GC analysis*, JMH benchmarking** Java/JVM platforms only
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Strategy (interesting, ear-marked)
[ ] Analyse & apply Squale reports[ ] Apply SonarGraph[ ] Apply Mutation testing (i.e. PITest, Mutator)[ ] Apply generative tests (QuickCheck)[ ] Apply Mutability Detector library[ ] Analyse using JitWatch (improve JIT attempts)[ ] Analyse using Censum (improve GC)
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Quality of Music - truth tableQuality of instrument (material)
How tuned the instrument is?
Skills & experience of the performer
Quality of music(outcome)
Bad Not tuned Not skilled / Skilled Very Bad
Bad Tuned Not skilled / Skilled Bad
Medicore Not tuned Not skilled / Skilled Below Average
Good Tuned / Not tuned Not skilled / Skilled Average
Good Tuned Skilled Good
Very good Tuned Highly skilled Very good
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Novice to expert...
In the beginning, learning from past experiences, building up knowledge and experience with repetitions, finally excelling with your own efforts...
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Layers of qualityContinuous Deployment*
Continuous Integration*
Code quality
Tools & Methods
(Developing) Good Habits
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Layers of quality (contd.)Continuous Deployment*
Continuous Integration*
See what Dr. Daniel Bryant has to say about the above:http://slidesha.re/1rKdOdUhttp://slidesha.re/VwKDB0
(Devops the TDD approach)
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