I got a Tomcat warning because the ThreadLocal of ThreadCtx where not destroyed when my webapp unloaded. To silence this warning (and remove the potential memory leak) I call ThreadCtx.cleanup(); in my code after I generated the PDF.

Should PdfBoxRenderer.cleanup() also remove the ThreadLocal? And should we document this somewhere, i.e. that you should call PdfBoxRenderer.cleanup() - at least in a web application?