Pipeline step return values can be captured.
Ramanathan, "findbugs" is a step added by the findbugs plugin. It was added in findbugs plugin version 4.70.
I don't know if the findbugs step returns a value you could use. I thought it had settings which would mark the build as stable or unstable depending on the detection of findbugs warnings. The Jenkins plugin development infrastructure can run findbugs as part of plugin continuous integration, and marks the build unstable when a findbugs warning is detected.
Mark Waite