Implementing Quality on Java projects

13,469 views
12,958 views

Published on

Gives 5 hands on tips on how to improve a specific aspect of Quality on Java projects

Published in: Technology
2 Comments
8 Likes
Statistics
Notes
No Downloads
Views
Total views
13,469
On SlideShare
0
From Embeds
0
Number of Embeds
3,589
Actions
Shares
0
Downloads
33
Comments
2
Likes
8
Embeds 0
No embeds

No notes for slide

Implementing Quality on Java projects

  1. Implementing Quality on Java projects Vincent Massol Committer XWiki XWiki SAS @vmassol 27 au 29 mars 2013Sunday, March 31, 13
  2. Vincent Massol • Speaker Bio • CTO XWiki SAS • Your Projects • XWiki (community-driven open source project) • Past: Maven, Apache Cargo, Apache Cactus, Pattern Testing • Other Credentials: • LesCastCodeurs podcast • Creator of OSSGTP open source group in Paris • 3 books: JUnit in Action, Maven: A Developer’s Notebook, BBWMSunday, March 31, 13
  3. What is Quality?Sunday, March 31, 13
  4. The XWiki project in summary • 9 years old • 28 active committers • 7 committers do 80% of work • 700K NCLOC • 11 commits/ day • 16 mails/daySunday, March 31, 13
  5. Examples of Quality actions • Coding rules (Checkstyle, ...) • Ensure API stability • Test coverage • Code reviews • Track bugs • License header checks • Don’t use Commons Lang 2.x • Release with Java 6 • Use SLF4J and don’t draw Log4J/ • Ensure javadoc exist JCL in dependencies • Prevent JAR hell • Automated build • Release often (every 2 weeks) • Automated unit tests • Collaborative design • Stable automated • Test on supported functional tests environments (DB & Browsers)Sunday, March 31, 13
  6. Quality Tip #1 API Stability 27 au 29 mars 2013Sunday, March 31, 13
  7. The Problem Class Not Found or Method Not FoundSunday, March 31, 13
  8. API Stability - Deprecations /** * ... * @deprecated since 2.4M1 use {@link #transform( * Block, TransformationContext)} */ @Deprecated void transform(XDOM dom, Syntax syntax) throws TransformationException;Sunday, March 31, 13
  9. API Stability - CLIRR (1/2) <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>clirr-maven-plugin</artifactId> <configuration> <ignored> <difference> <differenceType>7006</differenceType> <className>org/xwiki/.../MetaDataBlock</className> <method>org.xwiki....block.Block clone()</method> <to>org.xwiki.rendering.block.MetaDataBlock</to> <justification>XDOM#clone() doesnt clone the meta data</justification> </difference> ...Sunday, March 31, 13
  10. API Stability - CLIRR (2/2) Example from XWiki 5.0M1 Release notesSunday, March 31, 13
  11. API Stability - Internal Package Javadoc <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-javadoc-plugin <configuration> <excludePackageNames>*.internal.* </excludePackageNames> CLIRR <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>clirr-maven-plugin</artifactId> <excludes> <exclude>**/internal/**</exclude> <exclude>**/test/**</exclude>Sunday, March 31, 13
  12. API Stability - Legacy Module Aspect Weaving <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>aspectj-maven-plugin</...> ... <configuration> <weaveDependencies> <weaveDependency> <groupId>org.xwiki.rendering</...> <artifactId>xwiki-rendering-api</...> ... + “Legacy” ProfileSunday, March 31, 13
  13. API Stability - Young APIs /** * ... * @since 5.0M1 */ @Unstable(<optional explanation>) public EntityReference createEntityReference(String name,...) { ... } + max duration for keeping the annotation!Sunday, March 31, 13
  14. API Stability - Next steps • Annotation or package for SPI? • Better define when to use the @Unstable annotation • Not possible to add a new method to an existing Interface • Java 8 and Virtual Extension/Defender methods interface TestInterface {   public void testMe();   public void newMethod() default {     System.out.println("Default from interface");   } }Sunday, March 31, 13
  15. Quality Tip #2 JAR Hell 27 au 29 mars 2013Sunday, March 31, 13
  16. The Problem Class Not Found or Method Not Found or not working featureSunday, March 31, 13
  17. No duplicate classes @ runtime <plugin> <groupId>com.ning.maven.plugins</groupId> <artifactId>maven-duplicate-finder-plugin</artifactId> <executions> <execution> <phase>verify</phase> <goals> <goal>check</goal> </goals> <configuration> <failBuildInCaseOfConflict>true</...> <exceptions> ...Sunday, March 31, 13
  18. Surprising results... • Commons Beanutils bundles some classes from Commons Collections, apparently to avoid drawing a dependency to it... • Xalan bundles a lot of other projects (org/apache/xml/**, org/apache/ bcel/**, JLex/**, java_cup/**, org/apache/regexp/**). In addition, it even has these jars in its source tree without any indication about their versions... • stax-api, geronimo-stax-api_1.0_spec and xml-apis all draw javax.xml.stream.* classes • xmlbeans and xml-apis draw incompatible versions of org.w3c.dom.* classes 14 exceptions in total!Sunday, March 31, 13
  19. Maven: dependency version issue <dependencies> <dependency> Will run logback 0.9.9 <groupId>org.slf4j</groupId> with slf4J-api 1.4.0 <artifactId>slf4j-api</artifactId> instead of 1.5.0! <version>1.4.0</version> </dependency> <dependency> <groupId>ch.qos.logback</groupId> <artifactId>logback-classic</artifactId> <version>0.9.9</version> <!-- Depends on org.slf4j:slf4j-api:1.5.0 --> </dependency> </dependencies>Sunday, March 31, 13
  20. Maven: ensure correct version <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-enforcer-plugin</artifactId> <executions> <execution> <id>enforce-version-compatibility</id> <phase>verify</phase> <goals> <goal>enforce</goal> </goals> <configuration> <rules> <requireUpperBoundDeps/> </rules>Sunday, March 31, 13
  21. Quality Tip #3 Test Coverage 27 au 29 mars 2013Sunday, March 31, 13
  22. The Problem More bugs reported, overall quality goes down and harder to debug softwareSunday, March 31, 13
  23. Use Jacoco to fail the build <plugin> <groupId>org.jacoco</groupId> <artifactId>jacoco-maven-plugin</artifactId> <executions> <execution><id>jacoco-prepare</id> <goals><goal>prepare-agent</goal></goals> </execution> <execution><id>jacoco-check</id> <goals><goal>check</goal></goals> </execution> </executions> <configuration> <check> <instructionRatio>${xwiki.jacoco.instructionRatio}</...> </check>}Sunday, March 31, 13
  24. Strategy • When devs add code (and thus tests), increase the TPC percentage • Put the Jacoco check in “Quality” Maven Profile • Have a CI job to execute that profile regularly • About 15% overhead compared to build without checks • “Cheat mode”: Add easier-to-write testSunday, March 31, 13
  25. Quizz Time! Step 1: Building on my local machine gives the following: [INFO] --- jacoco-maven-plugin:0.6.2.201302030002:check (jacoco-check) [INFO] All coverage checks have been met. Step 2: Building on the CI machine gave: [INFO] --- jacoco-maven-plugin:0.6.2.201302030002:check (jacoco-check) [WARNING] Insufficient code coverage for INSTRUCTION: 75.52% < 75.53% Non determinism! Why?Sunday, March 31, 13
  26. Quizz Answer ... because the JVM is non deterministic! private Map componentEntries = new ConcurrentHashMap(); ... for (Map.Entry entry : componentEntries.entrySet()) { if (entry.getValue().instance == component) {   key = entry.getKey();     oldDescriptor = entry.getValue().descriptor;     break;   } }Sunday, March 31, 13
  27. Quality Tip #4 Functional Testing Stability (with Jenkins) 27 au 29 mars 2013Sunday, March 31, 13
  28. The Problem Too many false positives leading to developers not paying attention to CI emails anymore... leading to failing softwareSunday, March 31, 13
  29. False positives examples • The JVM has crashed • VNC is down (we run Selenium tests) • Browser crash (we run Selenium tests) • Git connection issue • Machine slowness (if XWiki cannot start under 2 minutes then it means the machine has some problems) • Nexus is down (we deploy our artifacts to a Nexus repository) • Connection issue (Read time out)Sunday, March 31, 13
  30. Step 1: Groovy PostBuild Plugin (1/2) def messages = [ [".*A fatal error has been detected by the Java Runtime Environment.*", "JVM Crash", "A JVM crash happened!"], [".*Error: cannot open display: :1.0.*", "VNC not running", "VNC connection issue!"], ... ] def shouldSendEmail = true messages.each { message -> if (manager.logContains(message.get(0))) { manager.addWarningBadge(message.get(1)) manager.createSummary("warning.gif").appendText(...) manager.buildUnstable() shouldSendEmail = false } }Sunday, March 31, 13
  31. Step 1: Groovy PostBuild Plugin (2/2) ... continued from previous slide... if (!shouldSendEmail) { def pa = new ParametersAction([ new BooleanParameterValue("noEmail", true) ]) manager.build.addAction(pa) }Sunday, March 31, 13
  32. Step 2: Mail Ext Plugin Pre-send Script import hudson.model.* build.actions.each { action -> if (action instanceof ParametersAction) { if (action.getParameter("noEmail")) { cancel = true } } }Sunday, March 31, 13
  33. Results + use the Scriptler plugin to automate configuration for all jobsSunday, March 31, 13
  34. Quality Tip #5 Bug Fixing Day 27 au 29 mars 2013Sunday, March 31, 13
  35. The Problem Bugs increasing, even simple to fix ones, devs focusing too much on new features (i.e. scope creep) vs fixing Bugs created vs closed what existsSunday, March 31, 13
  36. Bug Fixing Day • Every Thursday • Goal is to close the max number of bugs • Triaging: Can be closed with Won’t fix, Duplicate, Cannot Reproduce, etc • Close low hanging fruits in priority • Started with last 365 days then with last 547 days and currently with last 730 days (we need to catch up with 40 bugs!)Sunday, March 31, 13
  37. ResultsSunday, March 31, 13
  38. Conclusion 27 au 29 mars 2013Sunday, March 31, 13
  39. Parting words • Slowly add new quality check over time • Everyone must be on board • Favor Active Quality (i.e. make the build fail) over Passive checks • Be ready to adapt/remove checks if found not useful enough • Quality brings some risks: • Potentially less committers for your project (especially open source) • Project seen as “less fun”Sunday, March 31, 13
  40. Be proud of your Quality! “I have offended God and mankind because my work didnt reach the quality it should have.” Leonardo da Vinci, on his death bedSunday, March 31, 13

×