Application won't start

Question

i'm trying to write a java application but i can't get it to start. there are no error messages or warnings. can anyone help me please?
here's to code that i have written
import java.applet.*;
import java.awt.*;
import java.awt.Color;
import java.net.*;
import java.lang.*;
import java.io.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.AbstractButton;
public class db_queryTool extends JFrame {
JComboBox options;
GridBagLayout gbMain;
GridBagConstraints gbcMain;
public db_queryTool() {
     super();
public void init() {
     this.getContentPane().setLayout(gbMain);
     gbcMain.fill = GridBagConstraints.HORIZONTAL;
     gbcMain.anchor = GridBagConstraints.CENTER;
     options = new JComboBox();
     gbcMain.insets = new Insets(1,1,1,1);
     gbcMain.gridx = 0;
     gbcMain.gridy = 1;
     gbcMain.gridheight = 1;
     gbcMain.gridwidth = 1;
     gbcMain.weightx = 1.0;
     gbMain.setConstraints(options, gbcMain);
     add(options);
     setVisible(true);
public static void main(String[] args) {
     new db_queryTool();

Answer 1

Or try adding the init() method to your constructor
public db_queryTool() {
super();
init();