This book delivers all the information and sample code Java developers need in order to integrate new Java code with native and legacy applications that utilize platform-specific features. Sun's Java Native Interface (JNI) is the first API for building Java-enabled native applications that are binary compatible across multiple Java Virtual Machines. This book covers every aspect of the JNI API from the perspective of an experienced developer. Understand data structures, the JNI's relationship to file systems, native applications and native methods; the JNI library; and class construction with JNI. Learn how to use JNI to integrate Java and C++ code, and how to provide serial I/O from Java on both POSIX and Win32 platforms. The book includes a complete JNI reference and a full chapter on debugging. It's an essential resource for all Java programmers who need to take advantage of platform-specific features.