The Java Virtual Machine is the software implementation of a "CPU" designed to run compiled Java code. This includes stand-alone Java applications, as well as "applets" that are downloaded and run in Web browsers such as the NetScape Navigator. This book is a comprehensive programming guide for the Java Virtual Machine (JVM). The book is divided into two sections: the first section includes information on the semantics and structure of the JVM; the second section is a reference of the JVM instructions, or "opcodes." This book is intended to give readers a strong overview and reference of the JVM so that they may create their own implementations of the JVM or write their own compilers that create Java object code. The programming guide includes numerous examples written in Java assembly language.