user interface - Update GUI components after loading settings JAVA -

i have application gui sliders , comboboxes mainly. use sliders , combos change values , parameters in various classes in project. i'm trying implement possibility save , load parameters , have done using preferences api. can save , load parameters, when load them can see changes in values, works, gui not update reflect new values. there way tell gui so?

for instance have frequency slider changes frequency value in oscillator. if change value slider, save it, change value of slider again , load saved value, can hear has changed slider didn't move.(makes sense haven't told too). can bind position of slider frequency value somehow?

gui

    //osc1 slider     jslider osc1freqslider = new jslider(swingconstants.horizontal, min_osc_freq, max_osc_freq, note_a_freq);     osc1freqslider.setopaque(false);     osc1freqslider.setmajortickspacing(50000);     osc1freqslider.setminortickspacing(50);  osc1freqslider.addchangelistener(new changelistener() {         public void statechanged(changeevent e) {             jslider source = (jslider) e.getsource();             settings.setosc1freq((float)source.getvalue()/100);          }     }); 

settings class

public void setosc1freq(float freq) {     m_osc1freq = freq; } 

after setosc1freq( freq ) have jslider.setvalue( freq ).

the way in own projects never use free-standing primitive values float freq; instead, have observable class getter , setter, issues event when value changes, , wrap every single 1 of controls in class knows how interact such observable. so, every time value of control changes, value in observable changes too, also, every time program changes value of observable, control takes notice , updates too.

i think practically impossible write kind of gui without functionality, apparently seem contradicted existence of myriad of gui frameworks out there not support , force re-invent.