Nothing Displayed On Screen Java Swing Application -

import java.awt.*; import java.awt.event.*;  import javax.swing.*;  public class simultaneoussolver extends jframe implements actionlistener {      jtextfield  tfeq1x  = new jtextfield (20);     jtextfield  tfeq1y  = new jtextfield (20);     jtextfield  tfeq1num    = new jtextfield (20);      jtextfield  tfeq2x  = new jtextfield (20);     jtextfield  tfeq2y  = new jtextfield (20);     jtextfield  tfeq2num    = new jtextfield (20);      jlabel lblx1 = new jlabel ("x₁");     jlabel lbly1 = new jlabel ("y₁");     jlabel lblnum1  = new jlabel ("number₁");     jlabel lblequal1 = new jlabel ("=");      jlabel lblx2 = new jlabel ("x₂");     jlabel lbly2 = new jlabel ("y₂");     jlabel lblnum2  = new jlabel ("number₂");     jlabel lblequal2 = new jlabel ("=");      jtextarea empty = new jtextarea ("",1,20);      double x1, x2, y1, y2, num1, num2;     double solx, soly;      font font = new font("comic sans ms", font.bold, 14);      simultaneoussolver()     {         super ("simultaneous equation solver");         setdesign();         setsize(700,400);         setresizable(false);         setdefaultcloseoperation(exit_on_close);          jpanel panelequation1 = new jpanel(new gridlayout(1,7));         {             panelequation1.add(lblx1);             panelequation1.add(tfeq1x);             panelequation1.add(lbly1);             panelequation1.add(tfeq1y);             panelequation1.add(lblequal1);             panelequation1.add(lblnum1);             panelequation1.add(tfeq1num);         }          jpanel panelequation2 = new jpanel(new gridlayout(1,7));         {             panelequation2.add(lblx2);             panelequation2.add(tfeq2x);             panelequation2.add(lbly2);             panelequation2.add(tfeq2y);             panelequation2.add(lblequal2);             panelequation2.add(lblnum2);             panelequation2.add(tfeq2num);         }          setvisible(true);     }       public final void setdesign()      {         try          {             uimanager.setlookandfeel("com.sun.java.swing.plaf.nimbus.nimbuslookandfeel");         }            catch(exception e)          {            }     }      public static void main(string[] args)     {         new simultaneoussolver();     }  } 

ok, starting new application development using pure swing if possible, set objects , stuff , when try run application see if looks good, nothing shows except empty container.

add these 2 lines @ end of constructor.

setlayout(new gridlayout());  // sets layout frame - can choose 1 suitable layout add(panelequation1);  // adds 1st panel add(panelequation2); // adds 2nd panel