Listing the Interfaces That an Interface Extends : Interface « Reflection « Java Tutorial

public class Main {
  public static void main(String[] argv) throws Exception {
    Class cls = java.util.List.class;
    Class[] intfs = cls.getInterfaces(); // java.util.Collection

  }
}

7.2.Interface
	7.2.1.	The superclass of interfaces is always null
	7.2.2.	Listing the Interfaces That an Interface Extends
	7.2.3.	Checking whether String is an interface or class
	7.2.4.	If a class object is an interface or a class
	7.2.5.	Listing the Interfaces That a Class Implements
	7.2.6.	Although the type of o2 is an interface, getSuperclass() returns the object's superclass
	7.2.7.	The interfaces for a primitive type is an empty array
	7.2.8.	Return Returns true if type is implementing Map
	7.2.9.	Returns true if a class implements Serializable and false otherwise.
	7.2.10.	Get Super Interfaces
	7.2.11.	Get all interface and object classes that are generalizations of the provided class