Apache PDFBox is a popular open-source library that facilitates Java applications to work with PDF documents. Recently, we encountered a deadlock that surfaced in this library. In this post, we have shared how we troubleshot and identified the root cause of the problem.

What Is Deadlock?

First, let’s try to understand what “deadlock” means. Several technical definitions aren’t clear. The “deadlock” definition is one among them. Deadlock’s definition goes like this: