java - sorting file content

Hi, so i am working on a project where i will need to sort and select specific parts of the html code, so i was wondering if there were already built in libraries with functions that would help for instances manipulate the html file's content using tags (or something like that) or even something that would help sort or get specific content of a txt file. I already made a simple sorting algorithm, however it has some flaws and there is no need to reinvent the wheel if something like this already exists.
-Thanks in advance

Hey,
I used beautifullsoup to parse HTML with pyton, turns out they have a java library (Or whatever the name is) as well!
Take a look here: https://jsoup.org/
Hope it helps!