How To Refresh JTextArea

I created this JTextArea with some text in it. And it also has few variables.

Sth like that:

Java Code:

protected JTextArea textLog;
textLog = new JTextArea();
textLog.append("test: "+variable); mh_sh_highlight_all('java');

And now while I use button that changes variable value, in textLog variable still shows old value.

Tried to use remove(textLog); textLog.validate(); etc(remove, validate, revalidate, add, repaint), because it works fine with JButtons, but still, in textLog variable gives me old value.

like "you should use somethingvalidate(); while clickin button and it will works", not some shit for 3032 lines with 99% of code that I don't need to do what I want.