WINE: Warning miner for improving bug finders

•We propose a novel approach, WINE, that can reduce the inspection cost of validating warnings reported by lightweight bug finders. WINE addresses a problem of false positives caused by incorrect or incomplete implementations of the bug finders by extracting representative warnings.•We evaluated our approach with PMD, an open source bug finder, and 1,008 Java open source projects maintained by Apache Software Foundation. As a result, WINE extracted just about 2% of all warnings, which results in reducing validation costs for the generated warnings. Among the 2% of warnings, we could find the 28 false positive patterns caused by incorrect or incomplete implementations of PMD. The developers of PMD accepted all 28 issues that had never been reported for 13 years on average, and ten false-positive inducing issues were already fixed among them.•We simulated our approach in regression testing of PMD with twelve versions changes of PMD (6.25.0 to 6.37.0). As a result, we observed that WINE can effectively reduce the inspection costs by removing about 95% (8,845/9,268) changed warnings and extracting about 5% (423/9,268) as representative warnings.