public ResultSet getusers()
{
	try
	{
		sql="select userid,username,fullname,gender from users";
		st=con.prepareStatement(sql);
		rs=st.executeQuery();
		return rs;
	}
	catch(SQLException e)
	{
		e.printStackTrace();
		return null;
	}
}
	public static DefaultTableModel buildTableModel(ResultSet rs)
	        throws SQLException {

	    ResultSetMetaData metaData = rs.getMetaData();

	    // names of columns
	    Vector<String> columnNames = new Vector<String>();
	    int columnCount = metaData.getColumnCount();
	    for (int column = 1; column <= columnCount; column++) {
	        columnNames.add(metaData.getColumnName(column));
	    }

	    // data of the table
	    Vector<Vector<Object>> data = new Vector<Vector<Object>>();
	    while (rs.next()) {
	        Vector<Object> vector = new Vector<Object>();
	        for (int columnIndex = 1; columnIndex <= columnCount; columnIndex++) {
	            vector.add(rs.getObject(columnIndex));
	        }
	        data.add(vector);
	    }

	    return new DefaultTableModel(data, columnNames);
	}