diff --git a/jni/NativeFormats/fbreader/src/library/Book.cpp b/jni/NativeFormats/fbreader/src/library/Book.cpp
index 242d23cae..258cac6bf 100644
--- a/jni/NativeFormats/fbreader/src/library/Book.cpp
+++ b/jni/NativeFormats/fbreader/src/library/Book.cpp
@@ -94,17 +94,17 @@ shared_ptr<Book> Book::loadFromJavaBook(JNIEnv *env, jobject javaBook) {
 	env->DeleteLocalRef(javaFile);
 
 	std::string title;
-	javaString = (jstring) env->GetObjectField(javaBook, AndroidUtil::FID_Book_Title);
+	javaString = (jstring) env->CallObjectMethod(javaBook, AndroidUtil::MID_Book_getTitle);
 	AndroidUtil::extractJavaString(env, javaString, title);
 	env->DeleteLocalRef(javaString);
 
 	std::string language;
-	javaString = (jstring) env->GetObjectField(javaBook, AndroidUtil::FID_Book_Language);
+	javaString = (jstring) env->CallObjectMethod(javaBook, AndroidUtil::MID_Book_getLanguage);
 	AndroidUtil::extractJavaString(env, javaString, language);
 	env->DeleteLocalRef(javaString);
 
 	std::string encoding;
-	javaString = (jstring) env->GetObjectField(javaBook, AndroidUtil::FID_Book_Encoding);
+	javaString = (jstring) env->CallObjectMethod(javaBook, AndroidUtil::MID_Book_getEncoding);
 	AndroidUtil::extractJavaString(env, javaString, encoding);
 	env->DeleteLocalRef(javaString);
 
diff --git a/jni/NativeFormats/util/AndroidUtil.cpp b/jni/NativeFormats/util/AndroidUtil.cpp
index a7c340ee0..9cceac31d 100644
--- a/jni/NativeFormats/util/AndroidUtil.cpp
+++ b/jni/NativeFormats/util/AndroidUtil.cpp
@@ -54,9 +54,9 @@ jmethodID AndroidUtil::MID_ZLFile_isDirectory;
 jmethodID AndroidUtil::MID_ZLFile_size;
 
 jfieldID AndroidUtil::FID_Book_File;
-jfieldID AndroidUtil::FID_Book_Title;
-jfieldID AndroidUtil::FID_Book_Language;
-jfieldID AndroidUtil::FID_Book_Encoding;
+jmethodID AndroidUtil::MID_Book_getTitle;
+jmethodID AndroidUtil::MID_Book_getLanguage;
+jmethodID AndroidUtil::MID_Book_getEncoding;
 
 jmethodID AndroidUtil::SMID_Tag_getTag;
 
@@ -111,9 +111,9 @@ bool AndroidUtil::init(JavaVM* jvm) {
 
 	CHECK_NULL( cls = env->FindClass(Class_Book) );
 	CHECK_NULL( FID_Book_File = env->GetFieldID(cls, "File", "Lorg/geometerplus/zlibrary/core/filesystem/ZLFile;") );
-	CHECK_NULL( FID_Book_Title = env->GetFieldID(cls, "myTitle", "Ljava/lang/String;") );
-	CHECK_NULL( FID_Book_Language = env->GetFieldID(cls, "myLanguage", "Ljava/lang/String;") );
-	CHECK_NULL( FID_Book_Encoding = env->GetFieldID(cls, "myEncoding", "Ljava/lang/String;") );
+	CHECK_NULL( MID_Book_getTitle = env->GetMethodID(cls, "getTitle", "()Ljava/lang/String;") );
+	CHECK_NULL( MID_Book_getLanguage = env->GetMethodID(cls, "getLanguage", "()Ljava/lang/String;") );
+	CHECK_NULL( MID_Book_getEncoding = env->GetMethodID(cls, "getEncoding", "()Ljava/lang/String;") );
 	env->DeleteLocalRef(cls);
 
 	CHECK_NULL( cls = env->FindClass(Class_Tag) );
diff --git a/jni/NativeFormats/util/AndroidUtil.h b/jni/NativeFormats/util/AndroidUtil.h
index d05f636cf..82afa1d47 100644
--- a/jni/NativeFormats/util/AndroidUtil.h
+++ b/jni/NativeFormats/util/AndroidUtil.h
@@ -63,9 +63,9 @@ public:
 	static jmethodID SMID_PluginCollection_Instance;
 
 	static jfieldID FID_Book_File;
-	static jfieldID FID_Book_Title;
-	static jfieldID FID_Book_Language;
-	static jfieldID FID_Book_Encoding;
+	static jmethodID MID_Book_getTitle;
+	static jmethodID MID_Book_getLanguage;
+	static jmethodID MID_Book_getEncoding;
 
 	static jmethodID SMID_Tag_getTag;
 
diff --git a/proguard.cfg b/proguard.cfg
index 39c7d1150..17ba868f5 100755
--- a/proguard.cfg
+++ b/proguard.cfg
@@ -33,9 +33,14 @@
 }
 -keep class org.geometerplus.fbreader.library.Book
 -keepclassmembers class org.geometerplus.fbreader.library.Book {
+    public ** File;
+    public ** getTitle();
+    public ** getLanguage();
+    public ** getEncoding();
 }
 -keep class org.geometerplus.fbreader.library.Tag
 -keepclassmembers class org.geometerplus.fbreader.library.Tag {
+    public static ** getTag(**,**);
 }
 
 -keepclasseswithmembernames class * {