problem with library path on Windows 10

[Sean Ansari]

I am working on a sample Java Native Interface program, and was able to compile the Java portion with the latest 64-bit JDK. As you may know, this type of project also has a C source code. I have MinGw on my laptop, which run Windows 10. When I try to run the program, however I see the following error message:

C:\Users\sansari\Documents\source\java>ls
HelloJNI.c HelloJNI.class HelloJNI.exe HelloJNI.h HelloJNI.java hello.dll

C:\Users\sansari\Documents\source\java>rm hello.dll

C:\Users\sansari\Documents\source\java>gcc -Wl,--add-stdcall-alias -I"%JAVA_HOME%\include" -I"%JAVA_HOME%\include\win32" -shared -o HelloJNI.dll HelloJNI.c

C:\Users\sansari\Documents\source\java>java HelloJNI
Exception in thread "main" java.lang.UnsatisfiedLinkError: C:\Users\sansari\Documents\source\java\HelloJNI.dll: Can't load IA 32-bit .dll on a AMD 64-bit platform
at java.lang.ClassLoader$NativeLibrary.load(Native Method)
at java.lang.ClassLoader.loadLibrary0(Unknown Source)
at java.lang.ClassLoader.loadLibrary(Unknown Source)
at java.lang.Runtime.loadLibrary0(Unknown Source)
at java.lang.System.loadLibrary(Unknown Source)
at HelloJNI.<clinit>(HelloJNI.java:3)

C:\Users\sansari\Documents\source\java>java -Djava.library.path=. HelloJNI
Exception in thread "main" java.lang.UnsatisfiedLinkError: C:\Users\sansari\Documents\source\java\HelloJNI.dll: Can't load IA 32-bit .dll on a AMD 64-bit platform
at java.lang.ClassLoader$NativeLibrary.load(Native Method)
at java.lang.ClassLoader.loadLibrary0(Unknown Source)
at java.lang.ClassLoader.loadLibrary(Unknown Source)
at java.lang.Runtime.loadLibrary0(Unknown Source)
at java.lang.System.loadLibrary(Unknown Source)
at HelloJNI.<clinit>(HelloJNI.java:3)

C:\Users\sansari\Documents\source\java>ls
HelloJNI.c HelloJNI.class HelloJNI.dll HelloJNI.exe HelloJNI.h HelloJNI.java

C:\Users\sansari\Documents\source\java>ls
HelloJNI.c HelloJNI.class HelloJNI.dll HelloJNI.exe HelloJNI.h HelloJNI.java

Here is what is in my HelloJNI.java

public class HelloJNI {
   static {
      System.loadLibrary("HelloJNI"); // Load native library at runtime
                                   // hello.dll (Windows) or libhello.so (Unixes)
   }
 
   // Declare a native method sayHello() that receives nothing and returns void
   private native void sayHello();
   // Test Driver
   public static void main(String[] args) {
      new HelloJNI().sayHello();  // invoke the native method
   }
}

Here are the rest of the files:

C:\Users\sansari\Documents\source\java>ls
HelloJNI.c HelloJNI.class HelloJNI.dll HelloJNI.exe HelloJNI.h HelloJNI.java

I started out with the HelloJNI.java and compiled it with javac command. I then used javah to get HelloJNI.h. Here is what is in HelloJNI.c:

#include <jni.h>
#include <stdio.h>
#include "HelloJNI.h"

// Implementation of native method sayHello() of HelloJNI class
JNIEXPORT void JNICALL Java_HelloJNI_sayHello(JNIEnv *env, jobject thisObj) {
   printf("Hello World!\n");
   return;
}

[Campbell Ritchie]

Welcome to the Ranch

I can never seem to get anything to work in JNI myself, so I think it is beyond the “beginning” stage. I shall move you to another forum.

[Rob Spoor]

As far as I know, mingw is 32-bit only. You will need to use mingw-w64 instead.

[Sean Ansari]

Thanks. My error has changed now. Somehow I got over the earlier issue. Can you help me with this one?

C:\Users\sansari\Documents\source\java>java HelloJNI
Exception in thread "main" java.lang.UnsatisfiedLinkError: no HelloJNI.dll in java.library.path
        at java.lang.ClassLoader.loadLibrary(Unknown Source)
        at java.lang.Runtime.loadLibrary0(Unknown Source)
        at java.lang.System.loadLibrary(Unknown Source)
        at HelloJNI.<clinit>(HelloJNI.java:3)

[Sean Ansari]

Java Native Interface Tutorial

Here is the URL I am using to learn it.

[Sean Ansari]

I tried this also; no go ...

sansari@DESKTOP-E8J1RMD /c/users/sansari/documents/source/java
$ java -Djava.library.path=. HelloJNI
Exception in thread "main" java.lang.UnsatisfiedLinkError: no HelloJNI.dll in java.library.path
        at java.lang.ClassLoader.loadLibrary(Unknown Source)
        at java.lang.Runtime.loadLibrary0(Unknown Source)
        at java.lang.System.loadLibrary(Unknown Source)
        at HelloJNI.<clinit>(HelloJNI.java:3)