diff --git a/src/hidapi/android/hid.cpp b/src/hidapi/android/hid.cpp
index dd0edf1c6..e5af5ad2d 100644
--- a/src/hidapi/android/hid.cpp
+++ b/src/hidapi/android/hid.cpp
@@ -436,6 +436,12 @@ public:
 		g_JVM->AttachCurrentThread( &env, NULL );
 		pthread_setspecific( g_ThreadKey, (void*)env );
 
+		if ( !g_HIDDeviceManagerCallbackHandler )
+		{
+			LOGV( "Device open without callback handler" );
+			return false;
+		}
+
 		m_bIsWaitingForOpen = false;
 		m_bOpenResult = env->CallBooleanMethod( g_HIDDeviceManagerCallbackHandler, g_midHIDDeviceManagerOpen, m_nId );
 		ExceptionCheck( env, "BOpen" );
@@ -545,11 +551,18 @@ public:
 		g_JVM->AttachCurrentThread( &env, NULL );
 		pthread_setspecific( g_ThreadKey, (void*)env );
 
-		jbyteArray pBuf = NewByteArray( env, pData, nDataLen );
-		int nRet = env->CallIntMethod( g_HIDDeviceManagerCallbackHandler, g_midHIDDeviceManagerSendOutputReport, m_nId, pBuf );
-		ExceptionCheck( env, "SendOutputReport" );
-
-		env->DeleteLocalRef( pBuf );
+		int nRet = -1;
+		if ( g_HIDDeviceManagerCallbackHandler )
+		{
+			jbyteArray pBuf = NewByteArray( env, pData, nDataLen );
+			nRet = env->CallIntMethod( g_HIDDeviceManagerCallbackHandler, g_midHIDDeviceManagerSendOutputReport, m_nId, pBuf );
+			ExceptionCheck( env, "SendOutputReport" );
+			env->DeleteLocalRef( pBuf );
+		}
+		else
+		{
+			LOGV( "SendOutputReport without callback handler" );
+		}
 		return nRet;
 	}
 
@@ -560,10 +573,18 @@ public:
 		g_JVM->AttachCurrentThread( &env, NULL );
 		pthread_setspecific( g_ThreadKey, (void*)env );
 
-		jbyteArray pBuf = NewByteArray( env, pData, nDataLen );
-		int nRet = env->CallIntMethod( g_HIDDeviceManagerCallbackHandler, g_midHIDDeviceManagerSendFeatureReport, m_nId, pBuf );
-		ExceptionCheck( env, "SendFeatureReport" );
-		env->DeleteLocalRef( pBuf );
+		int nRet = -1;
+		if ( g_HIDDeviceManagerCallbackHandler )
+		{
+			jbyteArray pBuf = NewByteArray( env, pData, nDataLen );
+			nRet = env->CallIntMethod( g_HIDDeviceManagerCallbackHandler, g_midHIDDeviceManagerSendFeatureReport, m_nId, pBuf );
+			ExceptionCheck( env, "SendFeatureReport" );
+			env->DeleteLocalRef( pBuf );
+		}
+		else
+		{
+			LOGV( "SendFeatureReport without callback handler" );
+		}
 		return nRet;
 	}
 
@@ -587,6 +608,12 @@ public:
 		g_JVM->AttachCurrentThread( &env, NULL );
 		pthread_setspecific( g_ThreadKey, (void*)env );
 
+		if ( !g_HIDDeviceManagerCallbackHandler )
+		{
+			LOGV( "GetFeatureReport without callback handler" );
+			return -1;
+		}
+
 		{
 			hid_mutex_guard cvl( &m_cvLock );
 			if ( m_bIsWaitingForFeatureReport )
@@ -657,8 +684,11 @@ public:
 		g_JVM->AttachCurrentThread( &env, NULL );
 		pthread_setspecific( g_ThreadKey, (void*)env );
 
-		env->CallVoidMethod( g_HIDDeviceManagerCallbackHandler, g_midHIDDeviceManagerClose, m_nId );
-		ExceptionCheck( env, "Close" );
+		if ( g_HIDDeviceManagerCallbackHandler )
+		{
+			env->CallVoidMethod( g_HIDDeviceManagerCallbackHandler, g_midHIDDeviceManagerClose, m_nId );
+			ExceptionCheck( env, "Close" );
+		}
 	
 		hid_mutex_guard dataLock( &m_dataLock );
 		m_vecData.clear();