'private' sets the accessibility of the field to only the class the line is in (see Controlling Access to Members of a Class). 'static' means that the field belongs to the class and not to any particular object of that class. 'final' means that the field value will not change (it is a constant) (for the last 2, see Understanding Class Members). 'double' means that the field will hold value of the primitive type 'double' (see Primitive Data Types ). GRAVITY is the name assigned to the field (the names of constants are, by convention, given in all caps). '= 5.8' give the field an assigned value of '5.8'.