The Bug Catalog of the Maven Ecosystem
The MSR 2014 dataset: FindBugs run across Maven Central, catalogued by bug and by project.
The companion dataset to the MSR 2014 data paper. Maven Central holds the libraries most Java projects build on, which makes it a reasonable proxy for what the ecosystem actually runs; every artefact in the 2012 snapshot was analysed with FindBugs (external link, opens in a new tab), and the result is a catalogue of what it found, per bug pattern and per project.
Useful for asking which defect patterns are common in practice rather than in principle, and how that varies between projects and over versions.
The paper is on this site, and so is its security-focused companion, The Vulnerability Dataset of a Large Software Ecosystem, which cuts the same analysis down to its security findings.