java - not able to display two JLabel at the same time -

because i'm spending days find solution, take risk ridiculous. i'm trying add , display 2 jlabel inside gridbagconstraints. seems second jlabel overwrite first one. thinking put jlabels inside container wasn't able that

this got :

and why want :

the following code runnable reproduce problem

package myproblem;  import java.awt.basicstroke; import java.awt.borderlayout; import java.awt.color; import java.awt.dimension; import java.awt.eventqueue; import java.awt.font; import java.awt.graphics; import java.awt.graphics2d; import java.awt.gridbagconstraints; import java.awt.gridbaglayout; import java.awt.geom.line2d; import javax.swing.jframe; import javax.swing.jlabel; import javax.swing.jpanel; import javax.swing.swingconstants; import javax.swing.uimanager; import javax.swing.unsupportedlookandfeelexception; import javax.swing.border.border; import javax.swing.border.matteborder; public class myproblem { public int sizesquare = 50;  public static void main(string[] args) {     new myproblem(); }  public myproblem() {     eventqueue.invokelater(new runnable() {         @override         public void run() {             try {                 uimanager.setlookandfeel(uimanager.getsystemlookandfeelclassname());             } catch (classnotfoundexception | instantiationexception | illegalaccessexception | unsupportedlookandfeelexception ex) {             }             jframe frame = new jframe("myproblem");             frame.setdefaultcloseoperation(jframe.exit_on_close);             frame.setlayout(new borderlayout());             frame.add(new testpb());             frame.pack();             frame.setlocationrelativeto(null);             frame.setvisible(true);         }     }); }  public class testpb extends jpanel {      public testpb() {         setlayout(new gridbaglayout());          gridbagconstraints gbc = new gridbagconstraints();         border border = new matteborder(2, 2, 2, 2, color.black);         (int row = 0; row < 3; row++) {             (int col = 0; col < 3; col++) {                 gbc.gridx = col;                 gbc.gridy = row;                 fillsquare square = new fillsquare(sizesquare);                 square.setborder(border);                 square.setbackground(color.red);                  square.addlabel("45", "28");                 add(square, gbc);             }         }     } }  public class fillsquare extends jpanel {      public int sizesquare;     public jlabel labelright;     public jlabel labelleft;     public jlabel label;      public fillsquare(int sizesquare) {          this.sizesquare = sizesquare;         this.labelright = new jlabel("", swingconstants.right);         this.labelleft = new jlabel("", swingconstants.left);         this.label = new jlabel();     }      @override     public dimension getpreferredsize() {         return new dimension(sizesquare, sizesquare);     }      public void addlabel(string number1, string number2) {         add(addlabelleft(number1));         add(addlabelright(number2));     }      public jlabel addlabelright(string number) {         this.labelright.settext(number);         labelright.setpreferredsize(new dimension(sizesquare * 80 / 100, sizesquare * 40 / 100));         labelright.setfont(new font("arial", 0, sizesquare * 40 / 100));         labelright.setalignmenty(swingconstants.top);         return labelright;     }      public jlabel addlabelleft(string number) {         this.labelleft.settext(number);         labelleft.setpreferredsize(new dimension(25, 70));         labelleft.setfont(new font("arial", 0, sizesquare * 40 / 100));         labelleft.setalignmenty(swingconstants.bottom);         return labelleft;     }      @override     public void paintcomponent(graphics g) {         super.paintcomponent(g);         graphics2d g2d = (graphics2d) g;         g2d.setstroke(new basicstroke(2));         line2d line = new line2d.double(0, 0, 100, 100);         g2d.draw(line);     }  } } 

any , advice appreciated