I am not familiar with databases and I usually benefit from memory and data structures such as Maps. However right now my data is huge and by reading it into memory it quickly overflows and then the system entirely freezes (linux 12.04 LTS). 

So I thought maybe database is a good idea, however I need a quick and straightforward way of implementing and accessing it. It should also be a fast type of database. For instance Kyoto or something similar. 

So I'd like to put the following data in database:

```
HashMap<String, List> Index = new HashMap<String,List>();
List<String> sentences = new List<String>();

```

and then access them this way: Access by key for the hashmap, and access by List index for the List. 

Thanks in advance!