The document discusses a study of defect prediction for the Eclipse software project. Researchers analyzed Eclipse source code, bug reports, and change history from multiple releases to identify factors that correlate with higher defect counts. These factors include developer experience, test coverage, code complexity metrics, syntactic tokens, and dependencies on certain Eclipse packages. The researchers also collected and made available defect data and metrics for various Eclipse components.

2. Summary Project Eclipse (eclipse.org) Content Defect counts Complexity metrics Releases 2.0, 2.1, and 3.0 Level Packages and files URL www.st.cs.uni-sb.de/softevo/ More data Eclipse source code

3. Data Source Bugs Changes

6. Eclipse Bugs

7. Obtaining Data

10. Predictions at Work

11. Eclipse Bug Data <?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot;?> <!-- comments --> <defects project=&quot;eclipse&quot; release=&quot;2.0&quot; dataversion=&quot;1.0&quot;> <plug-in name=&quot;platform-launcher&quot;> <counts> <count id=&quot;pre&quot; value=&quot;0&quot; avg=&quot;0.0&quot; compilationunits=&quot;1&quot; max=&quot;0&quot;/> <count id=&quot;post&quot; value=&quot;0&quot; avg=&quot;0.0&quot; compilationunits=&quot;1&quot; max=&quot;0&quot;/> </counts> <package name=&quot;org.eclipse&quot;> <counts> <count id=&quot;pre&quot; value=&quot;0&quot; avg=&quot;0.0&quot; compilationunits=&quot;1&quot; max=&quot;0&quot;/> <count id=&quot;post&quot; value=&quot;0&quot; avg=&quot;0.0&quot; compilationunits=&quot;1&quot; max=&quot;0&quot;/> </counts> <package name=&quot;org.eclipse.core&quot;> <counts> <count id=&quot;pre&quot; value=&quot;0&quot; avg=&quot;0.0&quot; compilationunits=&quot;1&quot; max=&quot;0&quot;/> <count id=&quot;post&quot; value=&quot;0&quot; avg=&quot;0.0&quot; compilationunits=&quot;1&quot; max=&quot;0&quot;/> </counts> <package name=&quot;org.eclipse.core.launcher&quot;> <counts> <count id=&quot;pre&quot; value=&quot;0&quot; avg=&quot;0.0&quot; compilationunits=&quot;1&quot; max=&quot;0&quot;/> <count id=&quot;post&quot; value=&quot;0&quot; avg=&quot;0.0&quot; compilationunits=&quot;1&quot; max=&quot;0&quot;/> </counts> <compilationunit dir=&quot;/platform-launcher/library/&quot; base=&quot;Main.java&quot;> <counts> <count id=&quot;pre&quot; value=&quot;0&quot;/> <count id=&quot;post&quot; value=&quot;0&quot;/> </counts> </compilationunit> </package> </package> </package> </plug-in>

13. Eclipse Bugs

14. Where do bugs come from?

15. Is it the Developers? Does experience matter? Bug density correlates with experience!

16. How about Testing? Does code coverage predict bug density? Yes – the more tests, the more bugs!

17. History? I found lots of bugs here. Will there be more? Yes!

18. How about Metrics? Do code metrics predict bug density? Yes! (but only with history)

19. Syntactic Tokens? Which tokens predict bug density? imports • extends • implements

20. Eclipse Imports import org.eclipse.jdt.internal.compiler.lookup.*; import org.eclipse.jdt.internal.compiler.*; import org.eclipse.jdt.internal.compiler.ast.*; import org.eclipse.jdt.internal.compiler.util.*; ... import org.eclipse.pde.core.*; import org.eclipse.jface.wizard.*; import org.eclipse.ui.*; 14% of all components importing ui show a post-release defect 71% of all components importing compiler show a post-release defect Joint work with Adrian Schröter • Tom Zimmermann

21. Eclipse Imports Correlation with failure Correlation with success import org.eclipse.jdt.internal.compiler.lookup.*; import org.eclipse.jdt.internal.compiler.*; import org.eclipse.jdt.internal.compiler.ast.*; import org.eclipse.jdt.internal.compiler.util.*; ... import org.eclipse.pde.core.*; import org.eclipse.jface.wizard.*; import org.eclipse.ui.*;

22. What makes code buggy in the first place?