How to Programming with Jni

EDIT: Sorry I misunderstood your question. You can achieve this by using the other two ways that JNI API provides for creating objects (from docs): jobject NewObjectA(JNIEnv *env, jclass clazz, jmethodID methodID, const jvalue *args); jobject NewObjectV(JNIEnv *env, jclass clazz, jmethodID methodID, va_list args); NewObjectA Programmers place all arguments that...

Is there any chance the sizeof operator returns 0?

c,jni,sizeof

Objects in C always have a positive size, so no sizeof can never lead to 0. C doesn't allow empty struct or union types and also arrays must have a size that is bigger than 0. So there is no correct C type what soever that can return a value...

I receive error message when run JNI android app A/libc﹕ Fatal signal 11 (SIGSEGV) at 0xdeadd00d (code=1), thread 17729

java,android,c++,jni,native

The JNI side of this code is C, not C++, and C's laxer handling of pointer punning is part of the problem. Your code breaks on these two lines: jstring plainText = (*env)->NewStringUTF(env, "Hello from JNI ! Compiled with ABI 2222 "); return (*env)->NewStringUTF(env, plainText); because NewStringUTF has the signature...

Qt for Android - startActivityForResult equivalent does not work

java,android,qt,android-intent,jni

It was stupid mistake. It was wrong method signatures (setAction and setType. Correct, working code: QAndroidJniObject ACTION_GET_CONTENT = QAndroidJniObject::fromString("android.intent.action.GET_CONTENT"); QAndroidJniObject intent("android/content/Intent"); if (ACTION_GET_CONTENT.isValid() && intent.isValid()) { intent.callObjectMethod("setAction", "(Ljava/lang/String;)Landroid/content/Intent;", ACTION_GET_CONTENT.object<jstring>()); intent.callObjectMethod("setType",...

Can't understand this UnsatisfiedLinkError

If you have an overloaded method, you need to have the "full" JNI method name. The method name should also include the arguments types (so JNI can distinguish between the overloaded methods) JNIEXPORT jobject JNICALL Java_com_sdl4j_renderer_SDL_1Renderer_SDL_1CreateRenderer__Lcom_sdl4j_window_SDL_1Window_2II (JNIEnv *, jclass, jobject, jint, jint); Technically it's the same method name, then you...

When to use CallNonvirtualObjectMethod and its related methods?

android,android-studio,android-ndk,jni,android-gradle

As the documentation says, Call<Type>Method calls the method in the object's actual class, while CallNonvirtual<Type>Method calls the method in the class you specify. Consider this Java code: public class A { public void doSomething() { System.out.println("A.doSomething " + this.getClass().getName()); } } public class B extends A { public void doSomething()...

Java compilation error : /bin/ld:cannot find -ljvm

java,linux,gcc,jni,fuse

The jvm shared library will be found in a path under $JDK_HOME, however, you are not adding that path to your LDPATH make variable. You need to add -L${JDK_HOME}/lib to LDPATH (or wherever libjvm.so is found).

Android NDK and Gradle: Different Android.mk per build type

I think I've got a solution here. It's not as pretty as I would have liked it to be (esp. as it involves creating a temporary file), but I've tested it and it's working as intended. I've written this to use another Application.mk for debug builds, called Application-debug.mk. You can...

Error in VS2010 when trying to compile basic JNI Test Code

java,c++,visual-studio-2010,jni

Converting a comment into an answer, since apparently it helped solve the problem. One way to investigate the problems with MSBuild is by looking at detailed logs. From VS command prompt, cd to directory of the project, then execute command msbuild MyProject.vcxproj /v:d. This will build with detailed verbosity level....

NewGlobalRef/DeleteGlobalRef when returning object created in JNI

java,android-ndk,jni

When returning reference to New[Type]Array, or other object created in JNI method to Java, should we return result of NewGlobalRef call on created object? Only if you also want to retain that reference for use in future JNI calls without receiving it again as a JNI method parameter. And...

java jni transfer coordinates from c to java [closed]

java,c,arrays,jni

With JNI you can: Access Java fields from C. Call Java methods from C. If performance matters to you, you might want to have a data structure for these 4 points, pass a reference to that data structure to C, and in C update the fields of that data structure....

JVMTI - Get object for field in class

java,oracle,jvm,jni,jvmti

I just got a response on Facebook which answers my question. Here is the JNI reference: http://docs.oracle.com/javase/8/docs/technotes/guides/jni/spec/functions.html There you can find following methods: Get<type>Field Routines: NativeType Get<type>Field(JNIEnv *env, jobject obj, jfieldID fieldID); GetStatic<type>Field Routines: NativeType GetStatic<type>Field(JNIEnv *env, jclass clazz, jfieldID fieldID); So I can use GetObjectField() and GetStaticObjectField() which return...

Undefined reference for JNI methods

jni

You appear to be calling GetObjectArrayElement and friends as functions. They are not functions: they are function pointers within env. Call them as (*env)->GetObjectArrayElement(env, ...) ...

How does NDK work in Android - What is the order that NDK, JNI etc are used?

java,android,android-ndk,jvm,jni

The NDK is used to compile C/C++/asm code into binaries. You can do a lot of things with the NDK, like compiling executables, static prebuilts... but in the end, in the context of an Android application, you obtain one or more .so files (shared object libraries). From Java, you can...

AES_encrypt/AES_decrypt only returns part of a message

openssl,jni

AES_encrypt((const unsigned char *)origin, (unsigned char *)out, &aesKey); AES_encrypt operates on 16-byte blocks. 16 is the block size of AES. Effectively, you truncated your message. AES_decrypt(pout, outout, &aesKey); Here, you only decrypted 16 byes. The remainder of the buffer was back filled with 0. The 0 served as the...

JNI cache java array

java,c++,arrays,jni

Yes, the correct way to do this would be to use DirectByteBuffer. It comes with its own drawbacks, though. For example, such Buffer is not backed by array, and access to it from the Java side may be less efficient.

NDK - include error

android,android-ndk,jni

LOCAL_C_INCLUDE := /home/nemesis/adt-bundle-linux-x86_64-20140702/OpenCV-2.4.10-android-sdk/sdk/native/jni/include/opencv2 should be LOCAL_C_INCLUDES := /home/nemesis/adt-bundle-linux-x86_64-20140702/OpenCV-2.4.10-android-sdk/sdk/native/jni/include ie, it is plural and should point to the location from which the following is a relative path: #include <opencv2/core/core.hpp> ...

CallXXXMethod undefined using JNI in C

java,c,jni

There are few fixes required in the code: CallIntMethod should be (*env)->CallIntMethod class Test should be public Invocation should be jint age = (*env)->CallIntMethod(env, mod_obj, mid, NULL); Note that you need class name to call a static function but an object to call a method. (cls2 -> person) mid =...

JNI C++ to Java 32 bit image not showing properly

java,c++,colors,bitmap,jni

Isn't this just a mix in the order of the color components? I'm not familiar with any of these functions, but I believe that DIB_RGB_COLORS gives you the components in the “blue, green, red, reserved” order, whereas TYPE_4BYTE_ABGR is expecting the components in the “alpha, blue, green, red” order....

Can I cast native primitive type into a JNI primitive type without worrying about endianness?

android,opencv,android-ndk,jni

Then can I cast like this? Yes. JNI primitive types are machine-dependent. Your second example preserves whatever endian-ness was present in the source, which you haven't specified....

DCIM directory path on Android - Return Value

android,c++,android-ndk,jni

Environment.DIRECTORY_DCIM is the qualified Java name of the static String defined in the Environment class for the DCIM folder. However, it's isn't the actual value of the String, which is just "DCIM": public static String DIRECTORY_DCIM = "DCIM"; You need to pass the String value, not the Java name of...

Can't find OpenCV headers when compiling with ndk-build

You should add OpenCV's include directory to the LOCAL_C_INCLUDES otherwise the compiler won't find them LOCAL_C_INCLUDES := $(OPENCVROOT)/sdk/native/jni/include ...

ReleaseStringUTFChars not working for std::string

c++,jni,stdstring

You need to pass it exactly the same value you got from GetStringUTFChars(). You're not. You're passing whatever std::string gives you, which isn't necessarily the same thing.

Get length of jstring/char *?

java,c++,c,jni

Since the type of the variable is const char * it suggests that it's a nul terminated string, hence size_t length = strlen(npath); should be enough. Although, your call to bind() is wrong, you shold pass the size of the address structure, for which return bind(sockfd, sun, sizeof(sun)); should be...

How to return double[] in jni input argument

java,c++,arrays,jni,arguments

It should look as follows: JNIEXPORT jboolean JNICALL Java_com_test_getData___3D( JNIEnv* pEnv, jclass cls, jdoubleArray dArray ) { jboolean isCopy1; jdouble* srcArrayElems = pEnv->GetDoubleArrayElements(dArray, &isCopy1); jint n = pEnv->GetArrayLength(dArray); jboolean res = false; // here update srcArrayElems values, maybe set res to true if (isCopy1 == JNI_TRUE) { pEnv->ReleaseDoubleArrayElements(dArray, srcArrayElems, JNI_ABORT);...

issues in creating c linux library

java,c,openssl,jni,shared-libraries

BIO_new_mem_buf is in the openssl library. You have to link your library with -lcrypto (lower case L) or with what pkg-config --libs openssl gives you.

Is there any way to get actual type from a string value?

No, there is not built-in function that can do such mapping. But you can do this yourself using if-else or switch structure that is limited to your application. There is one library called "typedef.h" //It is available in C++, I don't know about C It has some functions like type.id()...

Is providing an implementation for all native methods required?

android,opencv,camera,jni,android-camera

It is not required to provide an implementation. You don't even need to compile a header file for your unimplemented methods. However, as is normal, you will get a java.lang.UnsatisfiedLinkError if you call the function....

How to replace cocos2d-x scene from Java?

java,android,jni,cocos2d-x

I tried this : extern "C" { void Java_org_cocos2dx_cpp_SceneChanger_nativeCallbackChangeScene(JNIEnv* env, jobject thiz) { Director::getInstance()->replaceScene(MyScene::createScene()); } }; and it replaces the scene successfully. Are you sure Director::getInstance() is a null pointer ? Make sure that you are running on OpenGL thread. Check your error log, look for a line saying call...

When did the Dalvik JNI start supporting pinning?

java,android,jni,dalvik

Dalvik never had a GC that moved objects around. We did the necessary prep work, such as explicitly pinning objects, but at the point where development on the copying collector was getting serious (mid-2011) all development efforts shifted to Art. The "global references" list holds all the JNI global references....

How to synchronize on java object in c++ passed from java to c++?

java,c++,multithreading,jni

You can use the JNI functions for Monitor Operations: jint MonitorEnter(JNIEnv *env, jobject obj); jint MonitorExit(JNIEnv *env, jobject obj); Of course this is C++ so you probably want to put it in a class (RAII): class MonitorLock { JNIEnv *env; jobject obj; public: MonitorLock(JNIEnv *in_env, jobject in_obj) : env(in_env), obj(in_obj)...

SIGSEGV when calling Java method from native pthread

java,c,multithreading,jni,pthreads

Turns out my suspicion was correct: jobject and jclass references are indeed local, i.e. valid only within the same thread and only until the current native method returns. See http://developer.android.com/training/articles/perf-jni.html#local_and_global_references. My approach of moving the reference-related code to the thread function was correct, except that I need to first convert...

Android Studio NDK return jint

android,android-ndk,jni,jint

A jint is a primitive type, so if you have included jni.h you can simply return one from the function - there is no need to allocate an Object as you were doing with NewStringUTF() for a String. JNIEXPORT jint JNICALL com_example_myapplication_MainActivity_getintONE(JNIEnv *env, jobject obj) { return 1; //or anything...

JVM Embedded into C, does not appear under running programs

java,jvm,jni

@apangin and @the8472 are both correct, you will not find the java process anywhere, using JNI_CreateJavaVM you are embedding the JVM functionalities in your process. I'll try to give evidence of this through references to the documentation (JNI is sparsely documented but i'll try). From the JNI Specification: Creating the...

setPreviewSize doesn't work propertly only in some devices

It seems to Nexus devices fails if you call: mCamera.setPreviewDisplay(mSurfaceHolder); before calling: Camera.Parameters parameters = mCamera.getParameters(); parameters.setPreviewFormat(ImageFormat.NV21); parameters.setPreviewSize(desiredSize.width, desiredSize.height); mCamera.setParameters(parameters); So, if you want your camera works on Nexus, first set preview size and then set surface holder to preview display....

Generating scip.jar file (mac)

jni,gmp,scip

The problem is that "gmp" is missing on your system. You have two options: Install the gmp library Compile SoPlex without gmp. For doing this call: make soplex GMP=false A similar issue might come up with the zlib. If this library is not installed on your system. If this is...

Getting Android Bluetooth Adapter Name from JNI/C++

android,c++,bluetooth,android-ndk,jni

First of all, you need to have permission to read this value (which you would need regardless of it being native). Add to AndroidManifest.xml: <uses-permission android:name="android.permission.BLUETOOTH"/> In native jni-land, things are a bit cumbersome. In short, this is what you need: Get class android.bluetooth.BluetoothAdapter Get static method BluetoothAdapter.getDefaultAdapter() Get method...

Win64 - JNI: UnsatisfiedLinkError: Can't find dependent libraries

java,dll,jni,unsatisfiedlinkerror,win64

Check for the following. 1) Make sure that there is no typo in the library name . incase of linux it should be some thing like System.load.library("mylib"); then the lib name should be like libmylib.so. 2) You need to add the location of the java library path like -Djava.library.path="path to...

Deploying JRE via JNI: jvm.dll not designed to run on Windows or […]

java,c++,jvm,jni

What exactly triggers the error message? This error is not unique to my application, so what documentation exists for that error? The error message is right. Something was wrong with my custom installation. Apparently the files lost data when extracted from the executable file. After literally copying in the...

Linking library and undefined reference to function in JNI

java,android,jni,shared-libraries,static-linking

Try to move the declaration of the sndfile module at the top of the file and then edit your native-audio-jni module by adding this: ... LOCAL_SHARED_LIBRARIES := sndfilelib or, alternatively, this: ... LOCAL_STATIC_LIBRARIES := sndfile ...

will cache jclass in native code prevent the class been unloaded

IMO, if you use the default stuff rather than play with class loaders, a reference to any method or field of MyClass from the other classes of your application is enough to prevent unloading of MyClass; just do not bother. What can happen in practice is that a process is...

Java native library architecture depend on JVM or OS?

The "bitness" of the native library must be the same as that of the JVM. If you are using a 32-bit JVM, you need a 32-bit native library (no matter if the OS is 32-bit or 64-bit). If you are using a 64-bit JVM, you need a 64-bit native library....

C++ DLL does not run on different machine

c++,visual-c++,jni

On machine it doesnt work open your dll in dependency walker. Examine the out put for errors, it is possible that you are using debug version of your dll which works fine on machine with visual studio or it maybe c++ redistributable which is missing on target machine

Accessed stale local reference passing short[] from JNI to Java

java,android,callback,jni

The problem here was that in : myObject = (*env)->NewObject(env, globalJavaReceiver, sendWaveData); I was trying to create an object from a wrong class function, not from the constructor So then I change this part in: myObject = (*env)->NewObject(env, globalJavaReceiver, nativeReceiverConstructor); where nativeReceiverConstructor is the jmethodID from the class constructor. Then...

How can I assign the NULL to a float/double variable?

eclipse,sqlite,eclipse-plugin,jni,klocwork

You cannot (and should not) assign a pointer to a normal variable. I really don't know why it allowed for some other normal data types, as you have mentioned. Compiler should have produced same warning equally for all assignment from pointer to other non-pointer data type NULL is a void...

Embed shared libs in Java Applets

java,deployment,applet,jni

..is it possible embed these libs inside the applet? No. Natives should be inside the root path of a separate Jar. There should be separate Jars for OS X, *nix and Windows. Then use Java Web Start to deploy the lot and reference each Jar containing natives in an...

JavaH failing to create C header file for JNI class

java,c++,class,jni,jna

When you use JNA, there is no longer any need to generate C headers nor compile any native code. When using direct mapping, methods declared native are automatically bound to their corresponding methods in the target shared library. JNA uses the method signatures and StdCall tagging interfaces to figure out...

convert std::string to jstring encoded using windows-1256

c++,jni,stdstring

Java strings use UTF-16. JNI has no concept of charset encodings other than UTF-8 and UTF-16 (unless you use JNI calls to access Java's Charset class directly, but Java only implements a small subset of charsets, and Windows-1256 is not one of them unless the underlying Java JVM specifically implements...

Klocwork plugin failed to run in eclipse with error “java.lang.UnsatisfiedLinkError: no sqlite_jni in java.library.path”

A little patience pays off... I read carefully the error message and it clearly says: Picked up _JAVA_OPTIONS: -Djava.net.preferIPv4Stack=true -Djava.library.path=".;C:\Program Files (x86)\myLib\win32" So I suddenly recall that I once set a environmental variable like this: _JAVA_OPTIONS = -Djava.net.preferIPv4Stack=true -Djava.library.path=".;C:\Program Files (x86)\myLib\win32" After I changed it to below, things begin to...

How do you add APP_CFLAGS to an android makefile

android-studio,makefile,jni,make

You could use LOCAL_CFLAGS for C/C++ code additional flags or LOCAL_CPPFLAGS for C++ code in Android build system. LOCAL_CFLAGS := -DTEST=1 ...

Is manually freeing resources of JNI method id required

java,android,memory-leaks,android-ndk,jni

No, the pointer returned from GetMethodID() must not be manually freed. UPDATE: JNI specification explicitly states when a function allocates something, what must be manually released. If a function does not allocate anything that must be freed then the specification usually does not contain such information explicitly written....

call main method in java module using JNI

java,c,jni

You're creating an Array of "myClass" instead of String stringClass = (*env)->FindClass(env, "java/lang/String"); args = (*env)->NewObjectArray(env, 2, stringClass, NULL); ...

error while loading shared libraries: libjvm.so:

jni

I found a very good example, one of the best on the web I guess, because the author wrote down the paths of each file he uses : Tutorial I still had a library problem so here is how I managed to get all working : Create the java and...

APK size exceed 50MB due to large amount of native libraries

java,android,jni,apk,native

I don't think it is possible to call loadLibrary on a .so that is not in the app's apk or on the device (expansions included). What you can do, though, is include your .so libraries inside an expansion file, create a Starter activity that extracts these SO to a system...

Android (ART) crash with error JNI DETECTED ERROR IN APPLICATION: jarray is an invalid stack indirect reference table or invalid reference

java,android,android-ndk,jni,leptonica

Following Alex Cohn 's advice I made the following code work: JAVA public byte[] getData() { byte[] buffer = nativeGetData(mNativePix); if (buffer == null) { throw new RuntimeException("native getData failed"); } return buffer; } private static native byte[] nativeGetData(long nativePix); Native jbyteArray Java_com_googlecode_leptonica_android_Pix_nativeGetData( JNIEnv *env, jclass clazz, jlong nativePix) {...

A resource was acquired at attached stack trace but never released. memory leak

StrictMode only reports failures to release objects that are explicitly monitored by StrictMode. It doesn't fire because you fail to release a string from JNI. The object allocated at the point in the code indicated by the stack trace needs to be released with an explicit close() call before the...

JNA causes UnsatisfiedLinkException with Unix Stat

java,c,linux,jni,jna

Have you looked at sys/stat.h to see if there's an actual declaration for stat() or if it's a C preprocessor macro? In the link above, stat will actually be stat64 if __USE_FILE_OFFSET64 is defined. To see if this is your problem, simply change the function name from stat to stat64....

Need to understand Andorid.mk better

jni,android.mk

FILE_LIST := $(wildcard $(LOCAL_PATH)/*.cpp) FILE_LIST += $(wildcard $(LOCAL_PATH)/**/*.cpp) FILE_LIST += $(wildcard $(LOCAL_PATH)/**/**/*.cpp) LOCAL_SRC_FILES := $(FILE_LIST:$(LOCAL_PATH)/%=%) The statements above will get a list of .cpp files in a maximize of three subdirectory. It uses the makefile built-in function for file name operation wildcard. LOCAL_SRC_FILES += $(patsubst $(LOCAL_PATH)/%, %, $(wildcard folder/**/*.cpp)) Similarly,...

does NewDirectByteBuffer create a copy in native code

java,c++,jni,native

Your use of DirectByteBuffer will almost certainly fail in spectacular, core-dumping, and unpredictable ways. And its behavior may vary between JVM implementations and operating systems. The problem is that your direct memory must remain valid for the lifetime of the DirectByteBuffer. Since your string is on the stack, it will...

Why does creating a C++11 thread cause a Fatal Signal?

android,multithreading,c++11,android-ndk,jni

According to this answer, the destructor of the thread will call std::terminate if the thread is still joinable at time of destruction. If you do not want to join the thread, you can fix this by detaching the thread instead. std::thread t(teste).detach(); ...

How to free memory allocated by native method on Java side?

java,c++,memory-leaks,jni,native

The Java GC should clean up any objects you allocate. See this answer for more details....

make native code access java methods and data members

java,android,c++,android-ndk,jni

Here is the sample code to set the boolean values, follow the same guideline to call the add method of the list. #include <stdio.h> #include <jni.h> #include "com_example_Foo.h" JNIEXPORT void JNICALL Java_com_example_Foo_someFunction (JNIEnv *env, jobject object, jobject returnObject) { jclass clzReturnObject = env->FindClass("com/example/ReturnObject"); jfieldID fieldA = env->GetFieldID(clzReturnObject, "a", "Z"); jfieldID...

What is the best way to save JNIEnv*

android,android-ndk,jni,jnienv

Caching a JNIEnv* is not a particularly good idea, since you can't use the same JNIEnv* across multiple threads, and might not even be able to use it for multiple native calls on the same thread (see http://android-developers.blogspot.se/2011/11/jni-local-reference-changes-in-ics.html) Writing a function that gets the JNIEnv* and attaches the current thread...

JNI to running process instead of using a library [closed]

java,c++,opencv,jni

You can invoke the JVM from C++, initialize your openCV based components and then run the java code. The basics of the invocation is explaned here, with a sample snippet. For an example to launch a Java component via a static method, you can look at the code at the...

Sending jbyte array to Java method failed using JNI

c++,qt,jni,qtandroidextras,jbytearray

The signature for a type of jbyteArray is [B. So the method call should be like : jniObject.callMethod<jint>("write","([BI)I",buffer,1000); ...

java.lang.UnsatisfiedLinkError when using JNI on ubuntu

java,garbage-collection,jni,jcuda

You need -Djava.library.path=. in the Makefile, and you need to load the library with System.loadLibrary("HelloJNI"); - no lib prefix, no .so suffix. The prefix and suffix are handled by Java - think of it, naming scheme on Windows is different (stupid but fact). And beware of the pitfall that you...

JNI libraries deallocate memory upon garbage collection?

Usually, such libraries do not deallocate memory due to garbage collection. Particularly: JCuda does not do this, and has no option or "mode" where this can be done. The reason is quite simple: It does not work. You'll often have a pattern like this: void doSomethingWithJCuda() { CUdeviceptr data =...

Are jfieldID and jmethodID bound to the specific class or can I use them on subclass objects?

Yes you can, but if the derived class overrides a method, it will introduce a new ID. With a superID calculated for super-class, you will be effectively calling obj.super.method() You can consider it as an analog of Java.lang.Class.getDeclaredMethod() and Java.lang.Class.getDeclaredFields()....

CallObjectMethod does not return a string

So, sorry for taking that long, but I got the problem resolved. Basically, it is a little typo causing the havoc (at least in your MWE): this->IDgetString = this->JNIEnvironment->GetStaticMethodID(this->javaClass , "getString" , "(()Ljava/lang/String;"); // ^ This parenthesis must be removed. Furthermore, I noticed you did not initialize the object. I...

Does jni::ExceptionDescribe implicitily clear the exception trace of the JNI environment object?

java,c++,exception-handling,jvm,jni

Apparently described behaviour was reported 18 years ago on Windows, please check here. Then with explanation "it looks like addressed" bug was closed during 2002. What you are describing looks very similar to mentioned bug.

How to manipulate CameraPreview bytearray through the JNI? (OpenCV)

java,android,c++,opencv,jni

I want to take the bytearray "data" and pass it to the JNI and apply some OpenCV filters so that the preview changes, without returning it. Unfortunately that's not possible. The byte array that is passed to onPreviewFrame() is just a copy of the preview frame, and any changes...

android jni return multiple variables

I can come up with three different ways to do it. Callback Call a Java method from your JNI code that takes multiple parameters, set a variable somewhere in your Java code, that you can retrieve when returning from the method. JNIEXPORT void JNICALL Java_my_package_name_JNIReturnExample_returnWithJavaCallback(JNIEnv *env, jobject javaThis, jfloat param1,...

How can I pass a struct to a kernel in JCuda

java,struct,cuda,jni,jcuda

(The author of JCuda here (not "JCUDA", please)) As mentioned in the forum post linked from the comment: It is not impossible to use structs in CUDA kernels and fill them from JCuda side. It is just very complicated, and rarely beneficial. For the reason of why it is rarely...

How do i call C/C++ code from Android using JNA?

android,c++,android-ndk,jni,jna

JNA provides a stub native library, libjnidispatch.so for a variety of platforms. You can build this library yourself, or extract one of the pre-built binaries from the project's lib/native/<platform>.jar packages. You include libjnidispatch.so in your Android project the way you would any other JNI library. This is required; you cannot...

Must I DeleteLocalRef an object I have called NewGlobalRef on?

In a garbage collected system, there is no such thing as object ownership. There are root object references and object references that are reachable directly or indirectly from the roots. (Weak references are not considered). Both JNI local references and JNI global references are root references. Creating additional references does...

java.lang.UnsatisfiedLinkError: org.thotheolh.jche.NativeBridge.loadPKCS11Module(Ljava/lang/String;)V

Found a very old 2012 Netbeans post to solve the problem. It is due to a few GCC compiler options missing when making the DLL files. Additional GCC Compiler Option: -Wl,--export-all-symbols -Wl,--add-stdcall-alias Reference: http://forums.netbeans.org/post-130319.html...

using i686-w64-mingw32-g++ for static libraries

static,jni

-Wl,--export-all-symbols -Wl,--add-stdcall-alias -v adding this solved my problem

Implementation of C in JNI , syntax changing

java,android,exception,jni,nosuchmethoderror

The JNI interface stuff is only needed on the boundary between Java and C. So, even if you have a thousand functions, if you're only calling two of those via JNI directly (with the others being called by those two, or called by other functions that those two call, and...

allocation and deallocation problems in JNI Android

android,c,jni

JNIEXPORT jint JNICALL Java_com_example_convolution_MainActivity_convolution (JNIEnv *env, jobject obj, jdoubleArray xreal, jdoubleArray ximag, jdoubleArray yreal, jdoubleArray yimag, jdoubleArray outreal, jdoubleArray outimag, jsize n) { jint status = 0; size_t size; size_t i; jdouble *xr, *xi, *yr, *yi, *or, *oi; __android_log_print(ANDROID_LOG_VERBOSE, "log", "start of convolution ", 1); if (SIZE_MAX / sizeof(double) <...

ejdb Java binding not working “no jejdb in java.library.path”

java,jni,ejdb

It is strange that you where able to build the code in the first place because on my side I needed to change stuff in configure, configure.ac and Makefile.in to be able for this to compile properly on MacOSX However, assuming that this is not a real issue, I did...

NoSuchMethodError in JNI to Java Exception

java.lang.AssertionError doesn't have the constructor mentioned in the error message. So you can't use ThrowNew(), which relies on that. You'll have to construct the exception yourself and use Throw()....

Set IplImage from object Bitmap and get result from IplImage to be a jIntArray

android,c++,opencv,jni,iplimage

I solved it by reviewing the JPG file creation in the Java file. the JPG creation also I used is based on ARGB so I needed to send an ARGB format to the Java code. Good Luck.

How to set a field from C++ to Java, using JNI

You will need methods "GetStaticFieldID()" and "SetStaticObjectField()". A Java String is just an object. (I assume you know how to create a Java String from a native string). See Accessing Static Fields in the JNI documentation. Edit: sample C (not C++) code (error checking omitted) jstring str; JNIEnv *env; jclass...

JNI method Executed automatically