Use JTextarea To Display Text And Then Prompt Users To Type In Certain Words

So currently I am trying to use a JTextarea to display text and I then prompt users to type in certain words. I have a few problems that I have encountered. Firstly when I use setText and then if I say setText again after that it erases the previous text that was set. Ideally I want to set text once per line in my whenever a certain task is fulfilled. For example if the text says enter y/n, I want the program to go to the next line once I say y or n. Another problem of course is when I setEditable to true I can edit the whole textArea. I just want to be able to edit the line which I am currently at. Is there anything that I can use that mimics the ACM console program, or even the console down below in most IDE's where everything appears to be done line by line?

Also here is an example of what I am trying to do, along with comments:

Java Code:

console.setText("Math is good!");
console.setText("What is 2+2?: "); //using getText gets the whole line, I want
//everything checked after the colon. That is where the input will be
if(line==4){
console.setText("That is correct");
}
else {
console.setText("That is incorrect");
}
//previous text lines are overriden with new ones. I don't want that, nor do I want to be able to edit the
//whole JtextArea mh_sh_highlight_all('java');

A JtextArea is just not getting the job done.