java - Program shows an empty window -


this question has answer here:

i have started program in java , sometimes, when run or debug it, shows empty white window. have no idea why, redebug , shows window correctly. btw, has nothing mysql connect void @ end.

here code:

package com.hinx.client;  import java.awt.*; import java.awt.event.actionevent; import java.awt.event.actionlistener; import javax.swing.*; import java.sql.*;   public class main {  public static void main(string [] args)  {     createwindow(); }   static void createwindow() {       //create panel     jpanel content = new jpanel();     content.setlayout(null);     //build frame     jframe frame = new jframe("hinx - marketplace apps - client alpha_0.0.1");     frame.setdefaultcloseoperation(jframe.exit_on_close);     frame.setsize(700, 233);     frame.setresizable(false);     frame.setlocationrelativeto(null);     frame.add(content);     frame.setvisible(true);      //create username label     jlabel username = new jlabel("username:");     username.setfont(new font("arial", font.bold, 15));     username.setforeground(color.white);     username.setbounds(34, 8, 100, 50);      //create password label     jlabel password = new jlabel("password:");     password.setfont(new font("arial", font.bold, 15));     password.setforeground(color.white);     password.setbounds(36, 85, 100, 50);      //create username field     jtextfield usernamet = new jtextfield(20);     usernamet.setbounds(12, 50, 125, 30);     usernamet.setborder(javax.swing.borderfactory.createemptyborder());      //create password field     jtextfield passwordt = new jtextfield(20);     passwordt.setbounds(12, 125, 125, 30);     passwordt.setborder(javax.swing.borderfactory.createemptyborder());      //add login button     jbutton login = new jbutton("login");     login.setbounds(0, 175, 150, 30);     login.addactionlistener(new actionlistener(){         public void actionperformed(actionevent e) {          }     });      //create login panel     jpanel loginpanel = new jpanel();     loginpanel.setlayout(null);     loginpanel.setbounds(0, 0, 150, 400);     loginpanel.setbackground(color.gray);      //add items loginpanel     loginpanel.add(username);     loginpanel.add(password);     loginpanel.add(usernamet);     loginpanel.add(passwordt);     loginpanel.add(login);      //add items content panel     content.add(loginpanel); }  protected void connect() {     string driver = "com.mysql.jdbc.driver";     string dbadress = "";     string dbname = "";     string username = "";     string password = "";     try     {         class.forname(driver).newinstance();         connection conn = drivermanager.getconnection(dbadress+dbname, username,password);         statement st = conn.createstatement();      } catch (exception e) {         e.printstacktrace();     } }  } 

frame.setvisible(true);

make last statement, after add components jframe.

also, best practice swing-related code in gui-thread (edt):

public static void main(string[] args) {     swingutilities.invokelater(new runnable()     {         @override         public void run()         {             createwindow();         }     }); }

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