Reflection - The Java Programming Language - page 654

The Class class provides a getresourceAsStream method to simplify getting
resources from a class's class loader. The preceding code could be writ-
ten more simply as
String book = "BoldPlayer.book";
InputStream in = BoldPlayer.class.getResourceAsStream(book);
Resource names must be made up of one or more valid identifiers sep-
arated by / characters, specifying a path to the resource. Typically, a
class loader will search for resources in the same places it will search for
class files.
Two other resource methods geTResource and getSystemResource return URL
objects that name the resources. The class java.net.URL is covered
briefly on page 725 ; it provides methods to use uniform resource locat-
ors to access resources. You can invoke the getContents method on the
URL objects returned by the class loader methods to get an object that
represents the contents of that URL .
The getresources method returns a java.util.Enumeration object (an older
variant of the Iterator you've seen before) that can step through URL ob-
jects for all the resources stored under a given name. The static method
getSystemResources does the same for system resources.
The resource-getting methods first ask the parent class loader for the
resource, or they ask the bootstrap class loader if there is no parent. If
the resource cannot be found, then findResource or findResources is in-
voked. Just as loadClass is built on top of a findClass that you provide
when you subclass ClassLoader , so the resource methods are built on top
of two methods that you can override to find resources:
public URL findResource(String name)
Returns a URL object for the resource of the given name , or
null if none was found. If there are multiple resources of the
same name the implementation determines which should be