Java Native Access

The definitive JNA reference (including an overview and usage details) is in the JavaDoc. Please read the overview. Questions, comments, or exploratory conversations should begin on the mailing list, although you may find it easier to find answers to already-solved problems on StackOverflow. JNA provides Java programs easy access to native shared libraries without writing anything but Java code - no JNI or native code is required. This functionality is comparable to Windows' Platform/Invoke and Python's ctypes. JNA allows you to call directly into native functions using natural Java method invocation. The Java call looks just like the call does in native code. Most calls require no special handling or configuration; no boilerplate or generated code is required. JNA uses a small JNI library stub to dynamically invoke native code. The developer uses a Java interface to describe functions and structures in the target native library. This makes it quite easy to take advantage of native platform features without incurring the high overhead of configuring and building JNI code for multiple platforms. Read this more in-depth description. While significant attention has been paid to performance, correctness and ease of use take priority. In addition, JNA includes a platform library with many native functions already mapped as well as a set of utility interfaces that simplify native access. Interesting Investigations/Experiments Drive Lego Mindstorm NXT by Emmanuel Pirsch. Detect User Inactivity by Olivier Chafik. There are also a number of examples and projects within the contrib directory of the JNA project itself. JNA will build on most linux-like platforms with a reasonable set of GNU tools and a JDK. See the native Makefile for native configurations that have been built and tested. If your platform is supported by libffi, then chances are you can build JNA for it. This is the core artifact of JNA and contains only the binding library and the core helper classes. This artifact holds cross-platform mappings and mappings for a number of commonly used platform functions, including a large number of Win32 mappings as well as a set of utility classes that simplify native access. The code is tested and the utility interfaces ensure that native memory management is taken care of correctly. Automatic mapping from Java to native functions, with simple mappings for all primitive data types Runs on most platforms which support Java Automatic conversion between C and Java strings, with customizable encoding/decoding Structure and Union arguments/return values, by reference and by value Function Pointers, (callbacks from native code to Java) as arguments and/or members of a struct Auto-generated Java proxies for native function pointers By-reference (pointer-to-type) arguments Java array and NIO Buffer arguments (primitive types and pointers) as pointer-to-buffer Nested structures and arrays Wide (wchar t-based) strings Native long support (32- or 64-bit as appropriate) Demo applications/examples Supported on 1.4 or later JVMs, including JavaME (earlier VMs may work with stubbed NIO support) Customizable marshalling/unmarshalling (argument and return value conversions) Customizable mapping from Java method to native function name, and customizable invocation to simulate C preprocessor function macros Support for automatic Windows ASCII/UNICODE function mappings Varargs support Type-safety for native pointers VM crash protection (optional) Optimized direct mapping for high-performance applications. COM support for early and late binding. COM/Typelib java code generator. All questions should be posted to the jna-users Google group. Issues can be submitted here on Github. What OS/CPU/architecture you're using (e.g. Windows 7 64-bit) Reference to your native interface definitions (i.e. C headers), if available The JNA mapping you're trying to use VM crash logs, if any Example native usage, and your attempted Java usage It's nearly imp