JNI error Exception in thread "main" java.lang.UnsatisfiedLinkError: (Ljava/lang/String;)Ljava/lang/String;

I have a native method that displays the file owner for a given path.

public class ACL{
static {
System.loadLibrary("owner"); // hello.dll (Windows) or libhello.so (Unixes)
}
// Declare native method
private native String displayFileOwner(String path);
public static void main(String[] args) {
String str = "C:/Users/pradeep-pt3689/eclipse-workspace/Permission/jni/owner.c";
System.out.println(":"+new ACL().displayFileOwner(str));
}
}

The code showing this error on running

> Exception in thread "main" java.lang.UnsatisfiedLinkError: ACL.displayFileOwner(Ljava/lang/String;)Ljava/lang/String;
at ACL.displayFileOwner(Native Method)
at ACL.main(ACL.java:10)

The native code is:

#include <jni.h>
#include <iostream>
#include <windows.h>
#include <tchar.h>
#include "ACL.h"
#include "accctrl.h"
#include "aclapi.h"
using namespace std;
JNIEXPORT jstring JNICALL Java_ACL_displayFileOwner(JNIEnv *env, jobject obj, jstring path)
{
jstring jstr=NULL;
const char *str=env->GetStringUTFChars(path, NULL);
DWORD dwRtnCode = 0;
PSID pSidOwner = NULL;
BOOL bRtnBool = TRUE;
LPTSTR AcctName = NULL;
LPTSTR DomainName = NULL;
DWORD dwAcctName = 1, dwDomainName = 1;
SID_NAME_USE eUse = SidTypeUnknown;
HANDLE hFile;
PSECURITY_DESCRIPTOR pSD = NULL;
// Get the handle of the file object.
hFile = CreateFile(
str,
GENERIC_READ,
FILE_SHARE_READ,
NULL,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL,
NULL);
// Check GetLastError for CreateFile error code.
if (hFile == INVALID_HANDLE_VALUE) {
DWORD dwErrorCode = 0;
dwErrorCode = GetLastError();
jstr = env->NewStringUTF("CreateFile error.\n");
return jstr;
}
// Get the owner SID of the file.
dwRtnCode = GetSecurityInfo(
hFile,
SE_FILE_OBJECT,
OWNER_SECURITY_INFORMATION,
&pSidOwner,
NULL,
NULL,
NULL,
&pSD);
// Check GetLastError for GetSecurityInfo error condition.
if (dwRtnCode != ERROR_SUCCESS) {
DWORD dwErrorCode = 0;
dwErrorCode = GetLastError();
jstr = env->NewStringUTF("GetSecurityInfo error.\n");
return jstr;
}
// First call to LookupAccountSid to get the buffer sizes.
bRtnBool = LookupAccountSid(
NULL,           // local computer
pSidOwner,
AcctName,
(LPDWORD)&dwAcctName,
DomainName,
(LPDWORD)&dwDomainName,
&eUse);
// Reallocate memory for the buffers.
AcctName = (LPTSTR)GlobalAlloc(
GMEM_FIXED,
dwAcctName);
// Check GetLastError for GlobalAlloc error condition.
if (AcctName == NULL) {
DWORD dwErrorCode = 0;
dwErrorCode = GetLastError();
jstr = env->NewStringUTF("GlobalAlloc error.\n");
return jstr;
}
DomainName = (LPTSTR)GlobalAlloc(
GMEM_FIXED,
dwDomainName);
// Check GetLastError for GlobalAlloc error condition.
if (DomainName == NULL) {
DWORD dwErrorCode = 0;
dwErrorCode = GetLastError();
jstr = env->NewStringUTF("GlobalAlloc error.\n");
return jstr;
}
// Second call to LookupAccountSid to get the account name.
bRtnBool = LookupAccountSid(
NULL,                   // name of local or remote computer
pSidOwner,              // security identifier
AcctName,               // account name buffer
(LPDWORD)&dwAcctName,   // size of account name buffer
DomainName,             // domain name
(LPDWORD)&dwDomainName, // size of domain name buffer
&eUse);                 // SID type
// Check GetLastError for LookupAccountSid error condition.
if (bRtnBool == FALSE) {
DWORD dwErrorCode = 0;
dwErrorCode = GetLastError();
if (dwErrorCode == ERROR_NONE_MAPPED)
jstr = env->NewStringUTF("Account owner not found for specified SID.\n");
else
jstr = env->NewStringUTF("Error in LookupAccountSid.\n");
return jstr;
} else if (bRtnBool == TRUE)
{// Print the account name.
jstr = env->NewStringUTF(AcctName);
env->ReleaseStringUTFChars(path, str);
}
return jstr;
}

The same jni methods I actually used in the web project to get the file path in textfield and print owner which works perfectly fine.
enter image description here

Anyone who's still facing this issue. Please try a simple JNI HelloWorld program execution and see if it works. In my case, a program passing string and returning name work perfectly fine, while the same method type passing file path and returning owner doesn't work.

JNIEXPORT jstring JNICALL Java_TestJNIString_sayHello(JNIEnv *env, jobject thisObj, jstring inJNIStr) {
const char *inCStr = (*env)->GetStringUTFChars(env, inJNIStr, NULL);
return (*env)->NewStringUTF(env, inCStr);
}

Now try to add different simple methods if you have, with above one in the same JNI code, and see it works. I had a complex method returning the ACL of a file with a return type string array. I tried executing a different method returning days of the week as string array and it works.

Now after executing the above JNI methods, make changes to the logic of your method but not return type and arguments passing.

It's weird but it worked.