Wrapper Classes

• Primitive types aren't classes
• Use wrappers when objects are expected
• Wrapper for each type:
  

  Integer Short Long Byte
  Character Float Double Boolean
  

• Auto-boxing and auto-unboxing
  

  ArrayList<Integer> numbers = new ArrayList<Integer>();
  numbers.add(13); // calls new Integer(13)
  int n = numbers.get(0); // calls intValue();