During November 2024, Tibor Tarnai focused on stabilizing PDF processing in the spring-projects/spring-ai repository by addressing a critical bug in the PagePdfDocumentReader component. He refactored the TextLine class to operate on a char array rather than a String, which reduced the risk of StringIndexOutOfBoundsException and improved both safety and performance. Tibor reinforced this change with targeted unit tests for TextLine behavior and exception handling, ensuring robust error management. His work demonstrated depth in Java, code refactoring, and exception handling, resulting in a more reliable PDF processing path and a measurable reduction in crash risk for the project.