java - Changing text on a JLabel from another class -

so, have been trying figure out little bit , cannot figure out how it. want 1 of buttons in class change text of jlabel in gui class.

here code gui class:`import java.awt.container;

import javax.swing.jbutton; import javax.swing.jframe; import javax.swing.jlabel; import javax.swing.jtextfield;   public class gui extends jframe{     container pane = getcontentpane();     jbutton guess = new jbutton("guess");     jbutton gen = new jbutton("generate number");     jtextfield userinput = new jtextfield();     jlabel numbers = new jlabel("press generate start.");     jlabel guessednum = new jlabel("");     jlabel error = new jlabel("");       public void creategui(){         final int width = 325;         final int height = 200;         final int centerwidth = width / 4;         final int centerheight = height / 4;          guesshandler guesshandle;         genhandler genhandle;          pane.setlayout(null);          guesshandle = new guesshandler();         guess.addactionlistener(guesshandle);         genhandle = new genhandler();         gen.addactionlistener(genhandle);           userinput.setbounds(centerwidth - 20, centerheight, 200, 20);         guess.setbounds(userinput.getx() - 35, (userinput.gety() + 25), 105, 50);         gen.setbounds((guess.getx() + 105), guess.gety(), 165, 50);         error.setbounds(70, 125, 300, 20);         numbers.setbounds(90, 0, 300, 20);         guessednum.setbounds(20, 25, 300, 20);           pane.add(userinput);         pane.add(guess);         pane.add(gen);         pane.add(numbers);         pane.add(guessednum);         pane.add(error);          setsize(width,height);         settitle("number guesser");         setdefaultcloseoperation(exit_on_close);         setvisible(true);         setresizable(false);         setlocation(350, 150);     } } 

and here code button trying change jlabel "error": `

import java.awt.event.actionevent; import java.awt.event.actionlistener;  import javax.swing.jbutton; import javax.swing.jlabel; import javax.swing.jtextfield;  public class guesshandler implements actionlistener{      public void actionperformed(actionevent e) {          gui gui = new gui();         gui.changepos(4, 50, 0, 300, 20);         gui.error.settext("hi guesshandler.java");      }  } 

first, add getter public access second class can access field. like,

public jlabel geterror() {      return error; } 

or (as @madprogrammer suggested in comments, mutator) like

public void seterror(string txt) {      error.settext(txt); } 

then modify second class, , pass instance of gui in constructor. like,

public class guesshandler implements actionlistener{     private gui gui;     public guesshandler(gui gui) {         this.gui = gui;     }     public void actionperformed(actionevent e) {         gui.changepos(4, 50, 0, 300, 20);         gui.seterror("hi guesshandler.java");     } }