Applications have a main method and can use public static methods of utility classes as well as instance methods of type I or type II classes.
Calling the static method random() in the utility Math class:
double d = Math.random(); // Math is the class name
// random is a static method
Calling the reset() instance method of the StopWatch class:
StopWatch c = new StopWatch(); // Must create an instance!
c.reset(); // c is an instance of the StopWatch class
// reset is an instance method