java - Slider Not Updating Label -

im new swing, tried making program creates slider , label. slider moved (form 1 16), label changes. however, label doesn't updated, , instead thread exceptions , other errors when slide slider. here full code:

package edu.cuny.brooklyn.cisc3120;  import java.awt.*; import javax.swing.*; import javax.swing.event.changeevent; import javax.swing.event.changelistener; import java.awt.event.*;  public class gui extends jframe {     private static final int limit = 4;     private static final int mininteger = 1;     private static final int maxinteger = 16;      private static jlabel currentguess;     private static jslider slider;      public gui()     {         setlayout(new flowlayout());          jslider slider = new jslider(jslider.horizontal, mininteger, maxinteger, 1);         add(slider);          slider.setmajortickspacing(1);         slider.setpaintlabels(true);         slider.setpaintticks(true);          currentguess = new jlabel("current guess: 1");         add(currentguess);          sliderevent e = new sliderevent();         slider.addchangelistener(e);     }      public static class sliderevent implements changelistener     {         public void statechanged(changeevent e)         {             currentguess.settext("current guess: " + slider.getvalue() );         }      }      public static void main(string[] args)     {         gui guessinggame = new gui();         guessinggame.setdefaultcloseoperation(jframe.exit_on_close);         guessinggame.settitle("guessing game");         guessinggame.setlocation(100, 100);         guessinggame.pack();         guessinggame.setvisible(true);     } } 

i reiterate i'm new swing. if i'm making stupid mistake, go easy on me please.

private static jslider slider;      public gui()     {         setlayout(new flowlayout());          jslider slider = new jslider(jslider.horizontal, mininteger, maxinteger, 1); 

you defining slider twice, once instance variable (which null) , once local variable.

get rid of local variable:

//jslider slider = new jslider(jslider.horizontal, mininteger, maxinteger, 1); slider = new jslider(jslider.horizontal, mininteger, maxinteger, 1); 

also, should not using static variables. indication of poor design. suggest @ section swing tutorial on how use sliders demo code show better program structure. download demo code modify requirements.