private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
    ArrayList<String> a = new ArrayList<String>();
        for (int i = 0; i<4;i++)
    {
        for (int j = 0; j<4;j++)
        {
        a.add((String) jTable1.getModel().getValueAt(i, j));
        }
    }
    Collections.shuffle(a);
    for (int i = 0;i<4;i++)
    {
        for (int j = 0; j<4;j++)
        {
        int k = 4*i + j;
        jTable1.getModel().setValueAt(a.get(k), j, i);
        }
    }
    }
    int PrevR=0;
    int PrevC=0;
    String PrevD = "";
    private void jTable1MouseClicked(java.awt.event.MouseEvent evt) {
    int a = jTable1.getSelectedRow();
    int b = jTable1.getSelectedColumn();
    String c = (String) jTable1.getModel().getValueAt(a, b);
    if (c == "")
    {
    if((Math.abs(b-PrevC) == 1 && Math.abs(a-PrevR)==0) || (Math.abs(b-PrevC) == 0 && Math.abs(a-PrevR) == 1))
        {
        jTable1.getModel().setValueAt(PrevD, a, b);
        jTable1.getModel().setValueAt("", PrevR, PrevC);
        }
    }
    String a1 = (String) jTable1.getModel().getValueAt(0,0);
    String a2 = (String) jTable1.getModel().getValueAt(0,1);
    String a3 = (String) jTable1.getModel().getValueAt(0,2);
    String a4 = (String) jTable1.getModel().getValueAt(0,3);
    String a5 = (String) jTable1.getModel().getValueAt(1,0);
    String a6 = (String) jTable1.getModel().getValueAt(1,1);
    String a7 = (String) jTable1.getModel().getValueAt(1,2);
    String a8 = (String) jTable1.getModel().getValueAt(1,3);
    String a9 = (String) jTable1.getModel().getValueAt(2,0);
    String a10 = (String) jTable1.getModel().getValueAt(2,1);
    String a11 = (String) jTable1.getModel().getValueAt(2,2);
    String a12 = (String) jTable1.getModel().getValueAt(2,3);
    String a13 = (String) jTable1.getModel().getValueAt(3,0);
    String a14 = (String) jTable1.getModel().getValueAt(3,1);
    String a15 = (String) jTable1.getModel().getValueAt(3,2);
    if ((a1=="1") && (a2=="2") && (a3=="3") && (a4=="4") && (a5=="5") && (a6=="6") && (a7=="7")
            && (a8=="8") && (a9=="9") && (a10=="10") && (a11=="11") && (a12=="12") && (a13=="13") && (a14=="14")
            && (a15=="15"))
           {
               JOptionPane.showMessageDialog(rootPane,"Игра закончена","Конец!",2);
           }
    PrevR=a;
    PrevC=b;
    PrevD = (String) jTable1.getValueAt(a, b);
    }