Java text file editor

Hello, I'm kind of new to java, have been programming a little before. Now the thing is, i need to make a program that will edit a .yml file, for example:

(user)Roger:
Password:pass123
Email:example@email.com

Now, i need a program that will delete Rogers data every time you start it. Rogers field wont be in any specific line or so, but i'd appreciate all help i could get. I'm making this little program for myself, so i have all the time i could get. If you know how to make it, then please reply, cause this is kind of important to me. I dont know, maybe it would be easier if my program copies the .yml file and deleting rogers field, and replacing the old file with the new one. This all is just something ive thought about, how to make it easier. I've seen lots of people that have a solution for it, but i dont really get all the system.out.writeln or whatever, cause, as i said, im new to Java. Once again, i appreciate all help i can ever get :)

Look at classes that will read and write text data. Read in the file line by line, saving them in an arraylist, removing the lines you don't want saved. When you have read all the lines and saved the right ones, close the file and then open it again to write on it. Copy the contents of the array list to the file.