When I use int stdId = 1; i. get no error but when I use int stdId = Integer.parseInt(id.getText()); and input the id in JForm i get exception error java.lang.NumberFormatException: For input string: “”

private void searchStudentActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_searchStudentActionPerformed
    // TODO add your handling code here:
    
    try{
        
        st = conn.createStatement();
        int stdId = 1;//Integer.parseInt(id.getText());
        
        rst = st.executeQuery("SELECT * FROM STUDENT WHERE stdId = '" + stdId + "'");
        
        if (rst.next()) {
            
            name.setText(rst.getString("stdName"));
            guardianName.setText(rst.getString("stdGuardianName"));
            bloodType.setText(rst.getString("stdBlood"));
            address.setText(rst.getString("stdAddress"));
            course.setText(rst.getString("stdClass"));
            phoneNum.setText(String.format("%s", rst.getInt("stdPhone")));

        } else{
            
            JOptionPane.showMessageDialog(null, "Record not found.");
            
        }
    } catch(Exception e){
        
        JOptionPane.showMessageDialog(null, e);
        
    }
    
}   

i also tried to use

"SELECT * FROM STUDENT WHERE id = '" + stdId + "'";
and 
"SELECT * FROM STUDENT WHERE stdId = '" + 1 + "'");
I still get same exception