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I'm a newer on java opencv, now i have a few confusion on Mat put functions.

The confusion is: the behavior of Mat.put(int ,int, double ...) and Mat.put(int, int, float[]) are different ( the 2 functions are in org.opencv.core.Mat.java line 2493 and line 2504). So i tried to look why by viewing source code and i found the native code are located in opencv-2.4.7/modules/java/generator/src/cpp/Mat.cpp

nPutF for put(int, int, float[])'s code:

   1931 JNIEXPORT jint JNICALL Java_org_opencv_core_Mat_nPutF
   1932     (JNIEnv* env, jclass, jlong self, jint row, jint col, jint count, jfloatArray vals);
   1933 
   1934 JNIEXPORT jint JNICALL Java_org_opencv_core_Mat_nPutF
   1935     (JNIEnv* env, jclass, jlong self, jint row, jint col, jint count, jfloatArray vals)
   1936 {
   1937     static const char method_name[] = "Mat::nPutF()";
   1938     try {
   1939         LOGD("%s", method_name);
   1940         cv::Mat* me = (cv::Mat*) self;
   1941         if(! self) return 0; // no native object behind
   1942         if(me->depth() != CV_32F) return 0; // incompatible type
   1943         if(me->rows<=row || me->cols<=col) return 0; // indexes out of range
   1944 
   1945         char* values = (char*)env->GetPrimitiveArrayCritical(vals, 0);
   1946         int res = mat_put<float>(me, row, col, count, values);
   1947         env->ReleasePrimitiveArrayCritical(vals, values, 0);
   1948         return res;
   1949     } catch(const std::exception &e) {
   1950         throwJavaException(env, &e, method_name);
   1951     } catch (...) {
   1952         throwJavaException(env, 0, method_name);
   1953     }
   1954 
   1955     return 0;
   1956 }

----------and here is mat_put

   1817 template<typename T> static int mat_put(cv::Mat* m, int row, int col, int count, char* buff)
   1818 {
   1819     if(! m) return 0;
   1820     if(! buff) return 0;
   1821 
   1822     count *= sizeof(T);
   1823     int rest = ((m->rows - row) * m->cols - col) * (int)m->elemSize();
   1824     if(count>rest) count = rest;
   1825     int res = count;
   1826 
   1827     if( m->isContinuous() )
   1828     {
   1829         memcpy(m->ptr(row, col), buff, count);
   1830     } else {
   1831         // row by row
   1832         int num = (m->cols - col) * (int)m->elemSize(); // 1st partial row
   1833         if(count<num) num = count;
   1834         uchar* data = m->ptr(row++, col);
   1835         while(count>0){
   1836             memcpy(data, buff, num);
   1837             **count -= num;**
   1838             buff += num;
   1839             num = m->cols * (int)m->elemSize();
   1840             if(count<num) num = count;
   1841             data = m->ptr(row++, 0);
   1842         }
   1843     }
   1844     return res;
   1845 }

but nPutD for put(int, int, double ...):

   1757 JNIEXPORT jint JNICALL Java_org_opencv_core_Mat_nPutD
   1758     (JNIEnv* env, jclass, jlong self, jint row, jint col, jint count, jdoubleArray vals);
   1759 
   1760 JNIEXPORT jint JNICALL Java_org_opencv_core_Mat_nPutD
   1761     (JNIEnv* env, jclass, jlong self, jint row, jint col, jint count, jdoubleArray vals)
   1762 {
   1763     static const char method_name[] = "Mat::nPutD()";
   1764     try {
   1765         LOGD("%s", method_name);
   1766         cv::Mat* me = (cv::Mat*) self;
   1767         if(!me || !me->data) return 0;  // no native object behind
   1768         if(me->rows<=row || me->cols<=col) return 0; // indexes out of range
   1769 
   1770         int rest = ((me->rows - row) * me->cols - col) * me->channels();
   1771         if(count>rest) count = rest;
   1772         int res = count;
   1773         double* values = (double*)env->GetPrimitiveArrayCritical(vals, 0);
   1774 ...