144. Introducing Java Native Interface (JNI)

Java Native Interface (JNI) was the first Java API meant to act as a bridge between JVM bytecode and native code written in another programming language (typically C/C++).

Let’s suppose that we plan to call via JNI a C function on a Windows 10, 64-bit machine.

For instance, let’s consider that we have a C function for summing two integers called sumTwoInt(int x, int y). This function is defined in a C shared library named math.dll. Calling such functions from Java (generally speaking, functions implemented by native shared libraries) starts with loading the proper shared native library via System.loadLibrary(String library). Next, we declare the C function in Java via the native keyword. Finally, we call it with the following code:

package modern.challenge;
public class Main {
  static { 
    System.loadLibrary("math");
  }
  private native long sumTwoInt(int x, int y);
  public static void main(String...