190: Highlights

• Java classes correspond to categories; Java class instances correspond to individuals.
• Class definitions generally include instance variables, also known as member variables, slots, or fields.
• If you want to define a class with public instance variables, then instantiate the following pattern:

  public class class name { 
   ... 
   public instance-variable type instance-variable name; 
   ... 
  } 
  

• If you want to declare a variable such that the value of the variable can be a class instance, then instantiate the following pattern:

  class name variable name; 
  

• If you want to create a new class instance, and you want to assign that new class instance to a variable, then instantiate the following pattern:

  variable name = new class name(); 
  

• If you want to declare a variable, initialized with a class instance, then instantiate the following pattern:

  class name variable name = new class name(); 
  

• If you wish to access an instance-variable value, then instantiate one of the following patterns:

  ... variable name.instance-variable name ... 
  variable name.instance-variable name = new-value expression;