I wish to implement awesomebar like search functionality during my java application. I love the actual way it searches the written text designs in between what. Will it uses lucene library or works like query around the database.

Which database will i decide for this particular pattern searching ?

Lots of Opera is supported by SQLite databases, including bookmarks and check history that are saved in [cde]. Although I not have the source to check on (for you to just download and take a look at just how they are doing it), I suspect that becasue it is SQLite then there's most likely something like a [cde] inside to complete the sub-string matching.