Primitive and Object Variables

  • Variables are represented on the stack as either:

    • A built-in primitive type (byte, short, int, long,
      char, float, double, or boolean)
      uses value semantics

      int i = 42; /* i holds value (42) */

    • An object type (extended from java.lang.Object)
      uses reference semantics (like a pointer)

      Button helpButton = new Button("Help");
      /* helpButton is an object ref */