Performance Improvements With C/C++
Now that you know how to combine Java and C/C++ code, you may think that C/C++ is always preferred over Java to achieve best performance. This is not true, and native code is not the answer to all your performance problems. Actually, you may sometimes experience a performance degradation when calling native code. While this may sound surprising, it really shouldn't as switching from Java space to native space is not without any cost. The Dalvik JIT compiler will also produce native code, which may be equivalent to or possibly even better than your own native code.
Let's consider the Fibonacci.computeIterativelyFaster()
method from Chapter 1 and its C implementation, as shown in Listing 2–16.
Listing 2–16. ...
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