diff --git a/src/android/kiwixreader.cpp b/src/android/kiwixreader.cpp
index 891b6650a..2a4259d53 100644
--- a/src/android/kiwixreader.cpp
+++ b/src/android/kiwixreader.cpp
@@ -95,7 +95,7 @@ Java_org_kiwix_kiwixlib_JNIKiwixReader_getFileSize(JNIEnv* env, jobject obj)
 
   try {
     int cSize = READER->getFileSize();
-    size = c2jni(cSize);
+    size = c2jni(cSize, env);
   } catch (std::exception& e) {
     __android_log_print(ANDROID_LOG_ERROR, "kiwix", "Unable to get ZIM file size");
     __android_log_print(ANDROID_LOG_ERROR, "kiwix", e.what());
@@ -234,7 +234,7 @@ JNIEXPORT jstring JNICALL Java_org_kiwix_kiwixlib_JNIKiwixReader_checkUrl(
     entry = entry.getFinalEntry();
     finalUrl = c2jni(entry.getPath(), env);
   } catch (std::exception& e) {
-    finalUrl = c2jni("", env);
+    finalUrl = c2jni(std::string(), env);
   }
   return finalUrl;
 }
@@ -433,7 +433,7 @@ Java_org_kiwix_kiwixlib_JNIKiwixReader_getArticleCount(JNIEnv* env, jobject obj)
   jint articleCount = 0;
   try {
     auto cArticleCount = READER->getArticleCount();
-    articleCount = c2jni(cArticleCount);
+    articleCount = c2jni(cArticleCount, env);
   } catch (std::exception& e) {
     __android_log_print(ANDROID_LOG_ERROR, "kiwix", "Unable to get article count.");
     __android_log_print(ANDROID_LOG_ERROR, "kiwix", e.what());
@@ -447,7 +447,7 @@ Java_org_kiwix_kiwixlib_JNIKiwixReader_getMediaCount(JNIEnv* env, jobject obj)
   jint mediaCount = 0;
   try {
     auto cMediaCount = READER->getMediaCount();
-    mediaCount = c2jni(cMediaCount);
+    mediaCount = c2jni(cMediaCount, env);
   } catch (std::exception& e) {
     __android_log_print(ANDROID_LOG_ERROR, "kiwix", "Unable to get media count.");
     __android_log_print(ANDROID_LOG_ERROR, "kiwix", e.what());
diff --git a/src/android/utils.h b/src/android/utils.h
index aeb5a4d35..87eac0ca2 100644
--- a/src/android/utils.h
+++ b/src/android/utils.h
@@ -93,15 +93,31 @@ struct LockedHandle : public Lock {
   operator bool() const { return (h->h != nullptr); }
 };
 
-/* c2jni type conversion functions */
-inline jboolean c2jni(const bool& val) { return val ? JNI_TRUE : JNI_FALSE; }
+template<typename T>
+struct JType { };
+
+template<> struct JType<bool>{ typedef jboolean type_t; };
+template<> struct JType<int>{ typedef jint type_t; };
+template<> struct JType<long>{ typedef jlong type_t; };
+template<> struct JType<uint64_t> { typedef jlong type_t; };
+template<> struct JType<uint32_t> { typedef jlong type_t; };
+template<> struct JType<std::string>{ typedef jstring type_t; };
+
+template<typename T>
+inline typename JType<T>::type_t c2jni(const T& val, JNIEnv* env) {
+  return static_cast<typename JType<T>::type_t>(val);
+}
+
+template<>
+inline jboolean c2jni(const bool& val, JNIEnv* env) { return val ? JNI_TRUE : JNI_FALSE; }
+
+template<>
 inline jstring c2jni(const std::string& val, JNIEnv* env)
 {
   return env->NewStringUTF(val.c_str());
 }
 
-inline jint c2jni(const int val) { return (jint)val; }
-inline jint c2jni(const unsigned val) { return (unsigned)val; }
+
 /* jni2c type conversion functions */
 inline bool jni2c(const jboolean& val) { return val == JNI_TRUE; }
 inline std::string jni2c(const jstring& val, JNIEnv* env)
@@ -141,7 +157,7 @@ inline void setBoolObjValue(const bool value, const jobject obj, JNIEnv* env)
 {
   jclass objClass = env->GetObjectClass(obj);
   jfieldID objFid = env->GetFieldID(objClass, "value", "Z");
-  env->SetIntField(obj, objFid, c2jni(value));
+  env->SetIntField(obj, objFid, c2jni(value, env));
 }
 
 inline void setPairObjValue(const std::string& filename, const int offset,