A Simple Class

• Each object is an instance of a class.
• The basics of a class are it's fields and methods (or, attributes and behaviors).

      class Body {
         public long idNum;
         public String nameFor;
         public Body orbits;
         public static long nextID = 0;
      }
  

• First declare the name of the class:

      Body mercury;
      Body earth;
  

• mercury and earth are references to objects of type Body.
• During it's existence, mercury may refer to any number of Body objects.
• Note - this version of Body is poorly designed.