File tesseract.log is empty in Linux Server

[Giuseppe Coniglio]

Hi to all :-)

I developed a Spring boot microservice that uses Tesseract 4.3.1 and PDFBox 2.0.22 (maven dependency in pom.xml)

The Linux server has Tesseract 4.1.1 installed (lepton-1.76.0)
Java project is done by this example https://colwil.com/how-to-extract-text-from-a-scanned-pdf-using-ocr-in-java/

I  set properties in my class

 ITesseract _tesseract = new Tesseract();
 _tesseract.setDatapath("tessdata");
 _tesseract.setLanguage("eng");
 _tesseract.setTessVariable("debug_file", "/opt/tesseract/tesseract.log");
 
 
 But tesseract.log is empty 0Kb :-(
 
 Why?
 
 thank a lots