1. The Comparable Interface
   1. Collections.sort(words)
   2. Natural Ordering and compareTo
      1. Comparison Function
      2. Natural Ordering
   3. ArrayLists do not have natural ordering
      1. Comparable interface
      2. public interface Comparable<T> {public int compareTo(T other);}
      3. Collections.sort(); is in the Comparable interface
2. Case Study: Vocabulary Comparison
   1. Some Efficiency Considerations
      1. Tradeoff between running time and memory
      2. add word to the end of list is better than contain
   2. Version 1: Compute Vocabulary
   3. Version 2: Compute Overlap
   4. Version 3: Complete Program
      1. regular expression
         1. [a-zA-Z']
         2. [^a-zA-Z']
         3. [^a-zA-Z']+ not including everything except words
3. ArrayLists
   1. basics
      1. no need to worry about add/remove strategies
   2. Generic Class
      1. ArrayList<E>
   3. Basic ArrayList Operations
      1. import java.util.*
   4. methods
      1. add
         1. add(index, <value>)
            1. expensive in time
      2. remove
         1. remove(index);
            1. expensive in time
      3. replace
         1. <name>.set(index, newValue)
      4. remove all
         1. clear
      5. no. of elements
         1. <name>.size()
      6. obtain item
         1. <name>.get(index)
   5. dynamic
   6. ArrayList Searching Methods
      1. contains
      2. indexOf
         1. first occurrence
      3. lastIndexOf
         1. index of last occurrence
   7. A Complete ArrayList Program
      1. stop words
   8. Adding to and Removing from an ArrayList
      1. intuitive way: adding from backwards
   9. Using the For-Each loop
      1. sequential problem
      2. iterate and modify cannot happen concurrently
      3. ConcurrentModificationException
   10. wrapper classes
       1. Arraylist<object type>
       2. wrapper class
          1. wraps(stores) primitive as an obj
          2. wrap: Integer y = new Integer(38);
          3. Unwrap: int number = y.intValue();
       3. boxing
          1. automatic conversion from primitive to object
          2. int to Integer
       4. unboxing
          1. wrapped obj to primitive data
          2. Integer to int