New to Java

Hi

I have a problem with a multi-line text, to be converted to one line, which I take from a JEditorPane.
I tried several things but it is still multi line

// the text is taken from JEditorPane
String str = jeditorPane.getText();
			
// replace "\n" with " "
str.replaceAll("\\n", " ");

or

// the text is taken from JEditorPane
String str = jeditorPane.getText();

Scanner s = new Scanner(str);

String line;
String completeText="";
while( ( line = str.nextLine() ) != null  ){
      completeText += line + " ";
}

In the fist code, it replaces all the "\n"'s with a space but it is still multi-line
in the second one, it doesn't change anything

So, what is wrong with these codes?

p.s. In the second code there (may) be a little mistake causing compile time error, please ignore that, my problem is with the logic of the code

thanks