Java™ Application Development on Linux - Dator

21.4 Review491entry in the enumeration is actually a binding that binds the name to either aname object or to a context object.If, when you encounter a context, you save the current context, set thecurrent context to the new context, and make the method recursive, you wouldwalk from the present context on down. In theory, you could set your initialcontext to “.” (which is the root of DNS) and this program would dump thewhole domain name system to you. 1121.3.3.2 Learning More about JNDIAs with so much in this book, we have had time and space to cover only thebasics. There is so much more to JNDI. For now we want to point you at Sun’sexcellent JNDI Tutorial. 12 JNDI is covered in more depth in many books,including JNDI API Tutorial and Reference: Building Directory-Enabled Java<strong>Application</strong>s by Rosanna Lee and Scott Seligman, ISBN 0201705028.21.3.4 Using JNDI with JBossFor our purposes, it is important to know that JBoss uses JNDI to providemuch of the EJB container infrastructure. The primary use is to look up theEJBs, as we shall see in the code examples in the following chapters.21.4REVIEWWe covered the basic concepts behind the various types of EJBs. We talkedabout the events in the life of a bean. From here we will go on to describe actualimplementations and discuss how a bean is written and deployed to a J2EEcontainer.11. If you are a relatively unschooled net hooligan, let us assure you that this is only “in theory.”Before you go off and attempt a DoS attack on the entire Internet with a simple Java class likethis, we have to tell you that JNDI DNS enumerations depend on a DNS protocol featurecalled zone transfers. Most high-level DNS servers will not do zone transfers at all, and manywill only accept zone transfer requests from internal addresses. Sorry.12. http://java.sun.com/products/jndi/tutorial