Partitions of outputs provided by some open-source static analysis tools

This document presents a partition of outputs provided by four popular open-source static analysis tools (SATs) regarding the detection of faults related to Null Pointer Exceptions (NPEs), namely PMD, SpotBugs, SonarLint, and Infer. The outputs of each SAT were partitioned into a small set of categories based on their message and practical meaning. These categories are (i) warnings or recommendations, (ii) faults that are not related to NPEs, but that are treated by the tool as having low to high severity, and (iii) NPE-related faults, which may be listed in several specific categories of the tools.