Document from file - how better store information about document?

Question

I have a text file that contains information about documents (content from groups than define the document - one row is one document). Every group content from fields (from 10 to 70 in every group). Document consist of 9 groups. In one documen can difference number of groups (> 1 group). E.g. one document can have 3 group1, 2 group6. In another document 2 group9, 1 group 6 and so on. I need to store document in DB and must edit document (by JFrame). To store document I use object MyDocument to store information about document.
3 solutions:
1. Store every group as list from hastables
public class MyDocument {
   private ArrayList<Hashtable<String, String>> group1;
   private ArrayList<Hashtable<String, String>> group2;
   private ArrayList<Hashtable<String, String>> group3;
   private ArrayList<Hashtable<String, String>> group4;
   private ArrayList<Hashtable<String, String>> group5;
   private ArrayList<Hashtable<String, String>> group6;
   private ArrayList<Hashtable<String, String>> group7;
   private ArrayList<Hashtable<String, String>> group8;
   private ArrayList<Hashtable<String, String>> group9; 2. Store all groups as one list from hashtables
public class MyDocument2 {
  private ArrayList<Hashtable<String, String>> allGroups;
} 3. Store groups as lists consist from individual objects (MyDocumentGroup1, MyDocumentGroup2 and so on.)
public class MyDocument3 {
   private ArrayList<MyDocumentGroup1> group1;
   private ArrayList<MyDocumentGroup2> group2;
   private ArrayList<MyDocumentGroup3> group3;
   private ArrayList<MyDocumentGroup4> group4;
   private ArrayList<MyDocumentGroup5> group5;
   private ArrayList<MyDocumentGroup6> group6;
   private ArrayList<MyDocumentGroup7> group7;
   private ArrayList<MyDocumentGroup8> group8;
   private ArrayList<MyDocumentGroup9> group9;
public class MyDocumentGroup1 {
   private ArrayList<Hashtable<String, String>> group1;
public class MyDocumentGroup9 {
   private ArrayList<Hashtable<String, String>> group9;
}What solutions is better? Or maybe has another solution?

Answer 1

Maybe better to store one document in ONE HashMap
public class M2Document {
     private HashMap<String, String> data = null;in the next format:
-------------key ---------value----------
GroupID_FN | some value
where, GroupID is ID of group, FN - field number
example:
-------------key ---------value----------
Group1_1 | some value
Group1_2 | some value
Group2_1 | some value
Group2_2 | some value
Group3_1 | some value
Group3_2 | some value