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I need to call C# function from java and to this I have created the following.
I have a create a java header file Authenticator.h , here is the code:
#include <jni.h>
/* Header for class Authenticator */
#ifndef _Included_Authenticator
#define _Included_Authenticator
#ifdef __cplusplus
extern "C" {
#endif
* Class: Authenticator
* Method: authenticate
* Signature: (Ljava/lang/String;Ljava/lang/String;)Z
JNIEXPORT jboolean JNICALL Java_Authenticator_authenticate
(JNIEnv *, jobject, jstring, jstring);
#ifdef __cplusplus
#endif
#endif
I have then create a C# function that Authenticate
namespace SharpAuthenticator
public class Authenticator
public bool Authenticate(String username,String password)
return username == "user" && password == "login";
Then I am trying to call the C# function from C++(project to create a dll) using the code below;
String^ toString(const char *str)
int len = (int)strlen(str);
array<unsigned char>^ a = gcnew array<unsigned char>(len);
int i = 0;
while (i < len)
a[i] = str[i];
return Encoding::UTF8->GetString(a);
bool authenticate(const char *username, const char *password)
SharpAuthenticator::Authenticator::Authenticate(toString(username), toString(password));
JNIEXPORT jboolean JNICALL Java_Authenticator_authenticate
(JNIEnv *env, jobject c, jstring name, jstring pass)
jboolean result;
jboolean isCopyUsername;
const char * username = env->GetStringUTFChars(name, &isCopyUsername);
jboolean isCopypassword;
const char * password = env->GetStringUTFChars(pass, &isCopypassword);
result = authenticate(username, password);
env->ReleaseStringUTFChars(name, username);
env->ReleaseStringUTFChars(pass, password);
return result;
And finnally create a dll that i need to call from java. The dll is created and I load it well in java but I get this error log in java. What could I be Missing.
# A fatal error has been detected by the Java Runtime Environment:
# Internal Error (0xe0434352), pid=9708, tid=7756
# JRE version: 7.0-b147
# Java VM: Java HotSpot(TM) Client VM (21.0-b17 mixed mode, sharing windows-x86 )
# Problematic frame:
# C [KERNELBASE.dll+0x812f]
# Failed to write core dump. Minidumps are not enabled by default on client versions of Windows
–
You can find csc.exe in install path of .NET framework. After that create java file:
public class Test{
public native String ping();
public static void main(String[] args){
System.load("/path/to/dll");
System.out.println("Java is running.");
Test t = new Test();
System.out.println("Trying to catch C# " + r.ping());
javac Test.java This generates a Test.class.
javah -jni Test This generates a Test.h file which will be included in
C++ code.
After that we need to create our C++ file:
#include "stdafx.h"
#include "JAVA/Test.h"
#include "MCPP/Test.h"
#pragma once
#using <mscorlib.dll>
#using "Test.netmodule"
JNIEXPORT jstring JNICALL Java_Test_ping(JNIEnv *env, jobject obj){
Test^ t = gcnew Test();
String^ ping = t->ping();
char* str = static_cast<char*>((System::Runtime::InteropServices::Marshal::StringToHGlobalAnsi(ping)).ToPointer());
char cap[128];
strcpy_s(cap, str);
return env->NewStringUTF(cap);
Finally:
c:\>java Test
I hope this helps you. A basic example to use function C# in Java.
Sources:
https://www.quora.com/How-common-is-the-problem-of-calling-C-methods-from-Java-Do-many-developers-come-across-such-necessity
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