Book Catalog Design [on hold]

You are given a catalog of books, which have following attributes:

Book Name
Book ID
Author ID
Publisher
Publish year
Category
Price
SoldCount

You are given a Author, which have following attributes:

Author Name
Author ID
Phone Number
DOB
Death Date

Implement following APIs on top of this catalog:

addBookToCatalog(Book)
getAllAuthor()
addAuthor()
getListOfCategories()
searchBook(by partial book name/author)
getMostSoldBooks(by author name/category, limit)

Expectations:

Maintain DB on memory.

I just want to know that:-(I am using java as my primary language.)
1-What Design Principle should i use?
2-And, what will be the "Interfaces and Abstract Classes" here?