- type mismatch
  - cannot assign val of incompatible type to var of another type
  - incompatible types represented differently in memory
  - makes assignments among types invalid
- wrapper class
  - utility class
  - surround primitive data with useful methods
  - e.g. type conversion
- Integer class
  - parseInt method
    - convert Strings to ints
    - if can't convert, causes error
- concatenation
  - + for strings
  - also for strings and numerical
    - automatically converts numbers to strings, then concatenates
- operator overloading
  - symbol used to represent > 1 operation
  - compiler determines meaning by context
    - treat as addition if both operations numerical (else concatenates)
    - evaluated left to right
    - result of concatenation is text
- DecimalFormat class
  - specify number of decimal places to display
  - package java.text

Quick Check
1. int inches;
   inches = Integer.parseInt(JOptionPane.showInputDialog(null, "What's your height in inches?"));
2. int lbs, kgs;
   lbs = Integer.parseInt(JOptionPane.showInputDialog(null, "How many pounds do you weigh?"));
   kgs = (int) ( (lbs * 453.592) / 1000 );
   JOptionPane.showOutputDialog("You weigh " + kgs + " kgs");