java - JNI %1 is not a valid Win32 application -

i'm running netbeans on 64-bit windows 8, jdk 1.7_25 (64-bit), following instructions beginning jni netbeans (https://netbeans.org/kb/docs/cnd/beginning-jni-linux.html)

the instructions linux, principle same windows believe (generating .dll file instead of .so, using win32 includes in jdk, etc)

i have cygwin64 installed cygwin32. using cygwin64, i'm able generate 64-bit dll c/c++ dynamic library project. however, when call system.load("path/to/jnitest.dll"), get:

exception in thread "main" java.lang.unsatisfiedlinkerror: c:\users\andrew\documents\netbeansprojects\jnitestlib\dist\jnitest.dll: %1 not valid win32 application @ java.lang.classloader$nativelibrary.load(native method)     @ java.lang.classloader.loadlibrary1(classloader.java:1957)     @ java.lang.classloader.loadlibrary0(classloader.java:1882)     @ java.lang.classloader.loadlibrary(classloader.java:1843)     @ java.lang.runtime.load0(runtime.java:795)     @ java.lang.system.load(system.java:1061)     @ jnitest.jnitest.main(jnitest.java:8) java result: 1 

from gather, case when loading 64-bit application on 32-bit virtual machine, netbeans.conf pointing 64-bit jvm.

additionally, when use 32-bit version of cygwin compile things , run, get

can't load ia 32-bit .dll on amd 64-bit platform 

i'm pretty sure i'm correctly generating dll file, it's simple helloworld printf follow jni tutorial. i'm new jni , c, i'm not sure start debugging. best i've done tried both 32 , 64-bit dlls, , i've made sure c compiler (cygwin) 64-bit, , jvm too.

i'd appreciate insight!

edit: here included files

=== java (jnitest.java) ===

package jnitest;  public class jnitest {      public static void main(string[] args) {         system.out.println("jvm: " + system.getproperty("sun.arch.data.model"));         system.load("c:\\users\\andrew\\documents\\netbeansprojects\\jnitestlib\\dist\\jnitest.dll");          new jnitest().dohello();     }      public native void dohello(); } 

=== generated javah header (jnitest_jnitest.h) ===

/* not edit file - machine generated */ #include <jni.h> /* header class jnitest_jnitest */  #ifndef _included_jnitest_jnitest #define _included_jnitest_jnitest #ifdef __cplusplus extern "c" { #endif /*  * class:     jnitest_jnitest  * method:    dohello  * signature: ()v  */ jniexport void jnicall java_jnitest_jnitest_dohello   (jnienv *, jobject);  #ifdef __cplusplus } #endif #endif 

=== c (jnitest.c) ===

#include <jni.h> #include "jnitest_jnitest.h"  jniexport void jnicall java_jnidemojava_main_nativeprint         (jnienv *env, jobject obj)  {     printf("\nhello world c\n");  } 

edit:

the problem seems dll, since can load other 64-bit dlls fine. thought cygwin might problem, changed compiler mingw-w64. compiled fine, , library loads, new exception:

exception in thread "main" java.lang.unsatisfiedlinkerror: jnitest.jnitest.dohello()v     @ jnitest.jnitest.dohello(native method)     @ jnitest.jnitest.main(jnitest.java:10) java result: 1 

some more digging found error thrown when classloader reads libs.size() here:

// invoked in vm class linking code.     static long findnative(classloader loader, string name) {         vector<nativelibrary> libs =             loader != null ? loader.nativelibraries : systemnativelibraries;         synchronized (libs) {             int size = libs.size();             (int = 0; < size; i++) {                 nativelibrary lib = libs.elementat(i);                 long entry = lib.find(name);                 if (entry != 0)                     return entry;             }         }         return 0;     } 

edit: answers!

finally figured out.

firstly, wrong cygwin64. using different 64-bit c compiler got rid of not valid win32 application error.

secondly, jnitest.c file's method signature incorrect. should have been:

java_jnitest_jnitest_dohello 

instead of

java_jnitest_main_dohello 

after changing that, works!

(though can't answer own question 6 hours... dum de dum)

finally figured out.

firstly, wrong cygwin64. using different 64-bit c compiler got rid of not valid win32 application error.

secondly, jnitest.c file's method signature incorrect. should have been:

java_jnitest_jnitest_dohello 

instead of

java_jnitest_main_dohello 

after changing that, works!