Java™ Native Interface: Programmer’s Guide and Specification, The

Chapter 3. Basic Types, Strings, and Arrays

One of the most common questions programmers ask when interfacing Java applications with native code is how data types in the Java programming language map to the data types in native programming languages such as C and C++. In the “Hello World!” example presented in the last chapter, we did not pass any arguments to the native method, nor did the native method return any result. The native method simply printed a message and returned.

In practice, most programs will need to pass arguments to native methods, and receive results from native methods as well. In this chapter, we will describe how to exchange data types between code written in the Java programming language and the native code that implements ...