Call method of class from another package without instantiating the class

Mihir :

Am new to Java and did not understand following piece of code from here

SimpleDateFormat format = new SimpleDateFormat(
        "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'", Locale.US);
format.setTimeZone(TimeZone.getTimeZone("UTC"));

After creating and instance of class SimpleDateFormat, which is from the java.text package, the setTomeZone method of the java.util package is being used.

Can any one please help me understand why we used setTimeZone method with instance of SimpleDateFormat class and NOT with instance of Calendar class?

Note: I went through a couple of articles that tell me how to call a method from another Java class or Java package. However this seemed different to me. I also noticed Calendar is an abstract class but unable to understand here.

curlyBraces :

A package contain classes and a class contains methods. In java.text we have SimpleDateFormat class. If you go to its public api, you can see that this class has a setTimeZone method (which it inherits from java.text.DateFormat class). So this method does belong to SimpleDateFormat class's API. Therefore it's wrong to say that setTimeZone method belongs to java.util package. The latter may contain some class that has a method with the same name, but those methods are not related.