Create 39-Book.java

// BlueJ Project: lesson4/book6
// Video: Working with the Book Text

        Counts how many times a given word occurs in this book.
        @param word a word of length >= 1
        @return the number of occurrences

        Counts how many times "Alice" occurs in this book.
        @return the number of occurrences

       Gets the first sentence of this book.
       @return the first sentence (including the period) of this book.

       Gets the second sentence of this book.
       @return the second sentence (including the period) of this book.

     * Calculates the number of characters (as in letters and
     * symbols, not people) in the book.
     * @return the number of letters and symbols in the book.

       Finds where the string "Mad Hatter" occurs for the first time in the book.
       @return the location of the first occurrence of the string