Use native code through JNITag(s): JNI

• With MSVC6, create a new Win32 DLL project (simple) and call it javahowto.
• In the same directory create a java source called JavaHowTo.java

  class JavaHowTo {
    public native String sayHello();
    static {
      System.loadLibrary("javahowto"); 
    }
  }

• Compile the Java program and use javah utility to generate the JavaHowTo.h header file.

  javah -jni JavaHowTo
  

• In MSVC6, add the JavaHowTo.h in your project header files
• In the Tools - Options menu, set the include directories to include the Java JNI headers files. They are located in [jdk dir]\include and [jdk dir]\include\win32 directories
• In the javahowto.cpp source, add

  #include "JavaHowTo.h" 
  
  JNIEXPORT jstring JNICALL Java_JavaHowTo_sayHello
    (JNIEnv *env, jobject obj) {
      return  env->NewStringUTF("Hello world");
  }

• Select the Release configuration and build the project.
• Copy the javahowto.dll in the same directory as the java program.
• Create this new java program

  public class JNIJavaHowTo {
    public static void main(String[] args) {
      JavaHowTo jht = new JavaHowTo();
      System.out.println(jht.sayHello());
      }
  }

• Compile and execute.