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

Chapter 4. Fields and Methods

Now that you know how the JNI lets native code access primitive types and reference types such as strings and arrays, the next step will be to learn how to interact with fields and methods in arbitrary objects. In addition to accessing fields, this includes making calls to methods implemented in the Java programming language from native code, commonly known as performing callbacks from native code.

We will begin by introducing the JNI functions that support field access and method callbacks. Later in this chapter we will discuss how to make such operations more efficient by using a simple but effective caching technique. In the last section, we will discuss the performance characteristics of calling native methods ...