how to webscrape particular link from google. (for example pdf downloadable links)

hi I have the code but I don't know how to get the output of only those link in google while searching which have .pdf or any document extension at the last for example (https://www.tutorialspoint.com/java/java_tutorial.pdf)

link of my code: https://github.com/vikaskc1/google-document-webscraping.git

I expect the output of scrape all the pdf links while searching. in this format https://www.tutorialspoint.com/java/java_tutorial.pdf