Java

A _ B _ C 
|   |_ D
|_F _ G_ H

private static void insertRecord() throws SQLException
{
	Connection con = null;
	Statement statement = null;
	try 
	{
	PreparedStatement PS = Connectionstring().prepareStatement("INSERT INTO LoginDetails(Username,Password) VALUES (?,?)");
	String User = tf_Uname.getText();
	  String _Pass = new String(tf_pass.getPassword());
	  //===========================================================================================================================================================
	  MessageDigest md = null;
		try {
			md = MessageDigest.getInstance("SHA-256");
		} 
		catch (NoSuchAlgorithmException e)
		{
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
      md.update(_Pass.getBytes());

      byte byteData[] = md.digest();

      //convert the byte to hex format method 1
      StringBuffer sb = new StringBuffer();
      for (int i = 0; i < byteData.length; i++) {
       sb.append(Integer.toString((byteData[i] & 0xff) + 0x100, 16).substring(1));
      }
      System.out.println("Hex format : " + sb.toString());

      //convert the byte to hex format method 2
      StringBuffer hexString = new StringBuffer();
  	for (int i=0;i<byteData.length;i++)
  	{
  		String hex=Integer.toHexString(0xff & byteData[i]);
 	     	if(hex.length()==1) hexString.append('0');
 	     	hexString.append(hex);
  	}
  	System.out.println("Hex format : " + hexString.toString());
	  
	  
	  //===========================================================================================================================================================
      
	    PS.setString(1, User);
		PS.setString(2, _Pass);
		PS.executeUpdate();							
		JOptionPane.showMessageDialog(null,"Your Data has been Inserted","Data Inserted",JOptionPane.INFORMATION_MESSAGE);
	} 
	catch (SQLException e)
	{

		System.out.println(e.getMessage()); 
	} 
	finally 
	{ 
		if (statement != null)
		{
			statement.close();				
			JOptionPane.showMessageDialog(null,"Statement is closed","Statement",JOptionPane.INFORMATION_MESSAGE);
		}

		if (con != null)
		{
			con.close();				
			JOptionPane.showMessageDialog(null,"Connection is closed!","Connection",JOptionPane.INFORMATION_MESSAGE );
		} 
	}		
}

private static void selectfromdb() throws SQLException
	{	
	    Statement stmt = Connectionstring().createStatement();
		ResultSet rs = stmt.executeQuery("SELECT Username,Password FROM LoginDetails where Username='"+tf_Fname+"' AND Password ='"+tf_Lname+"'");
		while (rs.next())
		{  
            String x = tf_Fname.getText();              
            String pass = new String(tf_Lname.getPassword());
            if (x.equals(rs.getString("Username"))) 
            {  
                if (pass.equals(rs.getString("Password")))
                {  
                	JOptionPane.showMessageDialog(null,"Login Successful! ","Success",JOptionPane.WARNING_MESSAGE);
                    //System.out.println("Logged in!");  
                }
                else
                {  
                	JOptionPane.showMessageDialog(null,"Login UNSuccessful! ","UNSuccessful",JOptionPane.WARNING_MESSAGE);
                   // System.out.println("Password did not match username!");  
                }  
            }  
        }             
				
		}