Andrew Chalk

Although we try to make our applications pure Java, outside forces sometimes make this impossible. We had such a case recently in our shop when we had to interface to an external device with an API that supported C language calls. This is a typical case for the Java Native Interface (JNI). The JNI provides Java programs with a gateway to other languages and enables applications written in other languages to invoke the Java Virtual Machine. This article focuses on the first of these two uses. Specifically, it discusses supporting a C/C++ API in Java to allow a Java application to use it. This is probably the situation in which the JNI is most frequently employed in production environments. Indeed, the seminal work on the JNI, The Java Native Interface: Programmer's Guide and Specification by Sheng Liang, devotes a chapter to this question. There's no theory involved, b... (more)