Reflection - The Java Programming Language - page 596

This program loops through the names provided on the command line,
obtains the Class object for each named type and invokes printType on
each of them. It must do this inside a TRy block in case there is no class
of the specified name. Here is its output when invoked on the utility
class java.util.HashMap :
class java.util.HashMap<K, V>
implements java.util.Map<K, V>
implements java.lang.Cloneable
implements java.io.Serializable
extends java.util.AbstractMap<K, V>
implements java.util.Map<K, V>
extends java.lang.Object
After the main method is the declaration of the output stream to use, by
default System.out . The String arrays are described shortly.
The printType method prints its own type parameter's description and
then invokes itself recursively to print the description of type 's super-
types. Because we initially have general Type objects, we first have to
convert them to Class objects. The depth parameter keeps track of how
far up the type hierarchy it has climbed, indenting each description line
according to its depth. The depth is incremented at each recursion level.
The labels array specifies how to label the class labels[0] is the label if
the type is a class; labels[1] is for interfaces; labels[2] for enums; and
labels [3] for annotation types. Note the order in which we check what
kind of type we havean enum type is a class, and an annotation type is
an interface, so we have to check for these more specific kinds of type
first.
Three arrays are defined for these labels: basic is used at the top level,
supercl is used for superclasses, and iFace is used for superinterfaces of
interfaces, which extend, not implement, each other. After we print the
right prefix, we use getCanonicalName to print the full name of the type.