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

Chapter 10. Traps and Pitfalls

To highlight the important techniques covered in previous chapters, this chapter covers a number of mistakes commonly made by JNI programmers. Each mistake described here has occurred in real-world projects.

Error Checking

The most common mistake when writing native methods is forgetting to check whether an error condition has occurred. Unlike the Java programming language, native languages do not offer standard exception mechanisms. The JNI does not rely on any particular native exception mechanism (such as C++ exceptions). As a result, programmers are required to perform explicit checks after every JNI function call that could possibly raise an exception. Not all JNI functions raise exceptions, but most can. Exception ...