jclass pointers aren't as cacheable as originally thought.

There is a way to do it.  We can try it later if we determine it's needed for performance reasons.  Otherwise, don't use static to cache them

java/jni/ZT1_jniutils.cpp

@@ -6,32 +6,16 @@
 extern "C" {
 #endif
 
-namespace
-{
-    static jclass arrayListClass = NULL;
-    static jmethodID arrayList_constructor = NULL;
-    static jmethodID arrayList_add = NULL;
-
-    static jclass inetAddressClass = NULL;
-    static jmethodID  inetAddress_getByAddress = NULL;
-}
-
 jobject createResultObject(JNIEnv *env, ZT1_ResultCode code)
 {
-    // cache the class so we don't have to
-    // look it up every time we need to create a java
-    // ResultCode object
-    static jclass resultClass = NULL;
+    jclass resultClass = NULL;
     
     jobject resultObject = NULL;
 
+    resultClass = env->FindClass("com/zerotierone/sdk/ResultCode");
     if(resultClass == NULL)
     {
-        resultClass = env->FindClass("com/zerotierone/sdk/ResultCode");
-        if(resultClass == NULL)
-        {
-            return NULL; // exception thrown
-        }
+        return NULL; // exception thrown
     }
 
     std::string fieldName;
@@ -65,8 +49,7 @@ jobject createResultObject(JNIEnv *env, ZT1_ResultCode code)
 
 jobject createVirtualNetworkStatus(JNIEnv *env, ZT1_VirtualNetworkStatus status)
 {
-    static jclass statusClass = NULL;
-    
+    jclass statusClass = NULL;
     jobject statusObject = NULL;
 
     if(statusClass == NULL)
@@ -110,16 +93,13 @@ jobject createVirtualNetworkStatus(JNIEnv *env, ZT1_VirtualNetworkStatus status)
 
 jobject createEvent(JNIEnv *env, ZT1_Event event)
 {
-    static jclass eventClass = NULL;
+    jclass eventClass = NULL;
     jobject eventObject = NULL;
 
+    eventClass = env->FindClass("com/zerotierone/sdk/Event");
     if(eventClass == NULL)
     {
-        eventClass = env->FindClass("com/zerotierone/sdk/Event");
-        if(eventClass == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
     std::string fieldName;
@@ -157,16 +137,13 @@ jobject createEvent(JNIEnv *env, ZT1_Event event)
 
 jobject createPeerRole(JNIEnv *env, ZT1_PeerRole role)
 {
-    static jclass peerRoleClass = NULL;
+    jclass peerRoleClass = NULL;
     jobject peerRoleObject = NULL;
 
+    peerRoleClass = env->FindClass("com/zerotierone/sdk/PeerRole");
     if(peerRoleClass == NULL)
     {
-        peerRoleClass = env->FindClass("com/zerotierone/sdk/PeerRole");
-        if(peerRoleClass == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
     std::string fieldName;
@@ -192,16 +169,13 @@ jobject createPeerRole(JNIEnv *env, ZT1_PeerRole role)
 
 jobject createVirtualNetworkType(JNIEnv *env, ZT1_VirtualNetworkType type)
 {
-    static jclass vntypeClass = NULL;
+    jclass vntypeClass = NULL;
     jobject vntypeObject = NULL;
 
+    vntypeClass = env->FindClass("com/zerotierone/sdk/VirtualNetworkType");
     if(vntypeClass == NULL)
     {
-        vntypeClass = env->FindClass("com/zerotierone/sdk/VirtualNetworkType");
-        if(vntypeClass == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
     std::string fieldName;
@@ -222,16 +196,13 @@ jobject createVirtualNetworkType(JNIEnv *env, ZT1_VirtualNetworkType type)
 
 jobject createVirtualNetworkConfigOperation(JNIEnv *env, ZT1_VirtualNetworkConfigOperation op)
 {
-    static jclass vnetConfigOpClass = NULL;
+    jclass vnetConfigOpClass = NULL;
     jobject vnetConfigOpObject = NULL;
 
+    vnetConfigOpClass = env->FindClass("com/zerotierone/sdk/VirtualNetworkConfigOperation");
     if(vnetConfigOpClass == NULL)
     {
-        vnetConfigOpClass = env->FindClass("com/zerotierone/sdk/VirtualNetworkConfigOperation");
-        if(vnetConfigOpClass == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
     std::string fieldName;
@@ -258,23 +229,20 @@ jobject createVirtualNetworkConfigOperation(JNIEnv *env, ZT1_VirtualNetworkConfi
 
 jobject newArrayList(JNIEnv *env)
 {
+    jclass arrayListClass = NULL;
+    jmethodID arrayList_constructor = NULL;
+
+    arrayListClass = env->FindClass("java/util/ArrayList");
     if(arrayListClass == NULL)
     {
-        arrayListClass = env->FindClass("java/util/ArrayList");
-        if(arrayListClass == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    arrayList_constructor = env->GetMethodID(
+        arrayListClass, "<init>", "()V");
     if(arrayList_constructor == NULL)
     {
-        arrayList_constructor = env->GetMethodID(
-            arrayListClass, "<init>", "()V");
-        if(arrayList_constructor == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
     jobject arrayListObj = env->NewObject(arrayListClass, arrayList_constructor);
@@ -287,13 +255,19 @@ bool appendItemToArrayList(JNIEnv *env, jobject array, jobject object)
     assert(array != NULL);
     assert(object != NULL);
 
+    jclass arrayListClass = NULL;
+    jmethodID arrayList_add = NULL;
+
+    arrayListClass = env->FindClass("java/util/ArrayList");
+    if(arrayListClass == NULL)
+    {
+        return NULL;
+    }
+
+    arrayList_add = env->GetMethodID(arrayListClass, "add", "(Ljava.lang.Object;)Z");
     if(arrayList_add == NULL)
     {
-        arrayList_add = env->GetMethodID(arrayListClass, "add", "(Ljava.lang.Object;)Z");
-        if(arrayList_add == NULL)
-        {
-            return false;
-        }
+        return false;
     }
 
     return env->CallBooleanMethod(array, arrayList_add, object);
@@ -301,26 +275,20 @@ bool appendItemToArrayList(JNIEnv *env, jobject array, jobject object)
 
 jobject newInetAddress(JNIEnv *env, const sockaddr_storage &addr)
 {
-    static jclass inetAddressClass = NULL;
-    static jmethodID inetAddress_getByAddress = NULL;
+    jclass inetAddressClass = NULL;
+    jmethodID inetAddress_getByAddress = NULL;
 
+    inetAddressClass = env->FindClass("java/net/InetAddress");
     if(inetAddressClass == NULL)
     {
-        inetAddressClass = env->FindClass("java/net/InetAddress");
-        if(inetAddressClass == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    inetAddress_getByAddress = env->GetStaticMethodID(
+        inetAddressClass, "getByAddress", "([B)Ljava/net/InetAddress;");
     if(inetAddress_getByAddress == NULL)
     {
-        inetAddress_getByAddress = env->GetStaticMethodID(
-            inetAddressClass, "getByAddress", "([B)Ljava/net/InetAddress;");
-        if(inetAddress_getByAddress == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
     jobject inetAddressObj = NULL;
@@ -361,16 +329,13 @@ jobject newInetAddress(JNIEnv *env, const sockaddr_storage &addr)
 
 jobject newInetSocketAddress(JNIEnv *env, const sockaddr_storage &addr)
 {
-    static jclass inetSocketAddressClass = NULL;
-    static jmethodID inetSocketAddress_constructor = NULL;
+    jclass inetSocketAddressClass = NULL;
+    jmethodID inetSocketAddress_constructor = NULL;
 
+    inetSocketAddressClass == env->FindClass("java/net/InetSocketAddress");
     if(inetSocketAddressClass == NULL)
     {
-        inetSocketAddressClass == env->FindClass("java/net/InetSocketAddress");
-        if(inetSocketAddressClass == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
     jobject inetAddressObject = newInetAddress(env, addr);
@@ -380,14 +345,11 @@ jobject newInetSocketAddress(JNIEnv *env, const sockaddr_storage &addr)
         return NULL;
     }
 
+    inetSocketAddress_constructor = env->GetMethodID(
+        inetSocketAddressClass, "<init>", "(Ljava/net/InetAddress;I)V");
     if(inetSocketAddress_constructor == NULL)
     {
-        inetSocketAddress_constructor = env->GetMethodID(
-            inetSocketAddressClass, "<init>", "(Ljava/net/InetAddress;I)V");
-        if(inetSocketAddress_constructor == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
     int port = 0;
@@ -413,29 +375,23 @@ jobject newInetSocketAddress(JNIEnv *env, const sockaddr_storage &addr)
 
 jobject newMulticastGroup(JNIEnv *env, const ZT1_MulticastGroup &mc)
 {
-    static jclass multicastGroupClass = NULL;
-    static jmethodID multicastGroup_constructor = NULL;
+    jclass multicastGroupClass = NULL;
+    jmethodID multicastGroup_constructor = NULL;
 
-    static jfieldID macField = NULL;
-    static jfieldID adiField = NULL;
+    jfieldID macField = NULL;
+    jfieldID adiField = NULL;
 
+    multicastGroupClass = env->FindClass("com/zerotierone/sdk/MulticastGroup");
     if(multicastGroupClass == NULL)
     {
-        multicastGroupClass = env->FindClass("com/zerotierone/sdk/MulticastGroup");
-        if(multicastGroupClass == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    multicastGroup_constructor = env->GetMethodID(
+        multicastGroupClass, "<init>", "()V");
     if(multicastGroup_constructor == NULL)
     {
-        multicastGroup_constructor = env->GetMethodID(
-            multicastGroupClass, "<init>", "()V");
-        if(multicastGroup_constructor == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
     jobject multicastGroupObj = env->NewObject(multicastGroupClass, multicastGroup_constructor);
@@ -470,87 +426,63 @@ jobject newMulticastGroup(JNIEnv *env, const ZT1_MulticastGroup &mc)
 
 jobject newPeerPhysicalPath(JNIEnv *env, const ZT1_PeerPhysicalPath &ppp)
 {
-    static jclass pppClass = NULL;
+    jclass pppClass = NULL;
 
-    static jfieldID addressField = NULL;
-    static jfieldID lastSendField = NULL;
-    static jfieldID lastReceiveField = NULL;
-    static jfieldID fixedField = NULL;
-    static jfieldID activeField = NULL;
-    static jfieldID preferredField = NULL;
+    jfieldID addressField = NULL;
+    jfieldID lastSendField = NULL;
+    jfieldID lastReceiveField = NULL;
+    jfieldID fixedField = NULL;
+    jfieldID activeField = NULL;
+    jfieldID preferredField = NULL;
 
-    static jmethodID ppp_constructor = NULL;
+    jmethodID ppp_constructor = NULL;
 
+    pppClass = env->FindClass("com/zerotierone/sdk/PeerPhysicalPath");
     if(pppClass == NULL)
     {
-        pppClass = env->FindClass("com/zerotierone/sdk/PeerPhysicalPath");
-        if(pppClass == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    addressField = env->GetFieldID(pppClass, "address", "Ljava/net/InetAddress;");
     if(addressField == NULL)
     {
-        addressField = env->GetFieldID(pppClass, "address", "Ljava/net/InetAddress;");
-        if(addressField == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    lastSendField = env->GetFieldID(pppClass, "lastSend", "J");
     if(lastSendField == NULL)
     {
-        lastSendField = env->GetFieldID(pppClass, "lastSend", "J");
-        if(lastSendField == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    lastReceiveField = env->GetFieldID(pppClass, "lastReceive", "J");
     if(lastReceiveField == NULL)
     {
-        lastReceiveField = env->GetFieldID(pppClass, "lastReceive", "J");
-        if(lastReceiveField == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    fixedField = env->GetFieldID(pppClass, "fixed", "Z");
     if(fixedField == NULL)
     {
-        fixedField = env->GetFieldID(pppClass, "fixed", "Z");
-        if(fixedField == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    activeField = env->GetFieldID(pppClass, "active", "Z");
     if(activeField == NULL)
     {
-        activeField = env->GetFieldID(pppClass, "active", "Z");
-        if(activeField == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    preferredField = env->GetFieldID(pppClass, "preferred", "Z");
     if(preferredField == NULL)
     {
-        preferredField = env->GetFieldID(pppClass, "preferred", "Z");
-        if(preferredField == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    ppp_constructor = env->GetMethodID(pppClass, "<init>", "()V");
     if(ppp_constructor == NULL)
     {
-        ppp_constructor = env->GetMethodID(pppClass, "<init>", "()V");
-        if(ppp_constructor == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
     jobject pppObject = env->NewObject(pppClass, ppp_constructor);
@@ -573,117 +505,84 @@ jobject newPeerPhysicalPath(JNIEnv *env, const ZT1_PeerPhysicalPath &ppp)
 
 jobject newPeer(JNIEnv *env, const ZT1_Peer &peer) 
 {
-    static jclass peerClass = NULL;
+    jclass peerClass = NULL;
 
-    static jfieldID addressField = NULL;
-    static jfieldID lastUnicastFrameField = NULL;
-    static jfieldID lastMulticastFrameField = NULL;
-    static jfieldID versionMajorField = NULL;
-    static jfieldID versionMinorField = NULL;
-    static jfieldID versionRevField = NULL;
-    static jfieldID latencyField = NULL;
-    static jfieldID roleField = NULL;
-    static jfieldID pathsField = NULL;
+    jfieldID addressField = NULL;
+    jfieldID lastUnicastFrameField = NULL;
+    jfieldID lastMulticastFrameField = NULL;
+    jfieldID versionMajorField = NULL;
+    jfieldID versionMinorField = NULL;
+    jfieldID versionRevField = NULL;
+    jfieldID latencyField = NULL;
+    jfieldID roleField = NULL;
+    jfieldID pathsField = NULL;
 
-    static jmethodID peer_constructor = NULL;
+    jmethodID peer_constructor = NULL;
 
+    peerClass = env->FindClass("com/zerotierone/sdk/Peer");
     if(peerClass == NULL)
     {
-        peerClass = env->FindClass("com/zerotierone/sdk/Peer");
-        if(peerClass == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    addressField = env->GetFieldID(peerClass, "address", "J");
     if(addressField == NULL)
     {
-        addressField = env->GetFieldID(peerClass, "address", "J");
-        if(addressField == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    lastUnicastFrameField = env->GetFieldID(peerClass, "lastUnicastFrame", "J");
     if(lastUnicastFrameField == NULL)
     {
-        lastUnicastFrameField = env->GetFieldID(peerClass, "lastUnicastFrame", "J");
-        if(lastUnicastFrameField == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    lastMulticastFrameField = env->GetFieldID(peerClass, "lastMulticastFrame", "J");
     if(lastMulticastFrameField == NULL)
     {
-        lastMulticastFrameField = env->GetFieldID(peerClass, "lastMulticastFrame", "J");
-        if(lastMulticastFrameField == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    versionMajorField = env->GetFieldID(peerClass, "versionMajor", "I");
     if(versionMajorField == NULL)
     {
-        versionMajorField = env->GetFieldID(peerClass, "versionMajor", "I");
-        if(versionMajorField == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    versionMinorField = env->GetFieldID(peerClass, "versionMinor", "I");
     if(versionMinorField == NULL)
     {
-        versionMinorField = env->GetFieldID(peerClass, "versionMinor", "I");
-        if(versionMinorField == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    versionRevField = env->GetFieldID(peerClass, "versionRev", "I");
     if(versionRevField == NULL)
     {
-        versionRevField = env->GetFieldID(peerClass, "versionRev", "I");
-        if(versionRevField == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    latencyField = env->GetFieldID(peerClass, "latency", "I");
     if(latencyField == NULL)
     {
-        latencyField = env->GetFieldID(peerClass, "latency", "I");
-        if(latencyField == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    roleField = env->GetFieldID(peerClass, "role", "Lcom/zerotierone/sdk/PeerRole;");
     if(roleField == NULL)
     {
-        roleField = env->GetFieldID(peerClass, "role", "Lcom/zerotierone/sdk/PeerRole;");
-        if(roleField == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    pathsField = env->GetFieldID(peerClass, "paths", "Ljava.util.ArrayList;");
     if(pathsField == NULL)
     {
-        pathsField = env->GetFieldID(peerClass, "paths", "Ljava.util.ArrayList;");
-        if(pathsField == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    peer_constructor = env->GetMethodID(peerClass, "<init>", "()V");
     if(peer_constructor == NULL)
     {
-        peer_constructor = env->GetMethodID(peerClass, "<init>", "()V");
-        if(peer_constructor == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
     jobject peerObject = env->NewObject(peerClass, peer_constructor);
@@ -715,22 +614,22 @@ jobject newPeer(JNIEnv *env, const ZT1_Peer &peer)
 
 jobject newNetworkConfig(JNIEnv *env, const ZT1_VirtualNetworkConfig &vnetConfig)
 {
-    static jclass vnetConfigClass = NULL;
-    static jmethodID vnetConfig_constructor = NULL;
-    static jfieldID nwidField = NULL;
-    static jfieldID macField = NULL;
-    static jfieldID nameField = NULL;
-    static jfieldID statusField = NULL;
-    static jfieldID typeField = NULL;
-    static jfieldID mtuField = NULL;
-    static jfieldID dhcpField = NULL;
-    static jfieldID bridgeField = NULL;
-    static jfieldID broadcastEnabledField = NULL;
-    static jfieldID portErrorField = NULL;
-    static jfieldID enabledField = NULL;
-    static jfieldID netconfRevisionField = NULL;
-    static jfieldID multicastSubscriptionsField = NULL;
-    static jfieldID assignedAddressesField = NULL;
+    jclass vnetConfigClass = NULL;
+    jmethodID vnetConfig_constructor = NULL;
+    jfieldID nwidField = NULL;
+    jfieldID macField = NULL;
+    jfieldID nameField = NULL;
+    jfieldID statusField = NULL;
+    jfieldID typeField = NULL;
+    jfieldID mtuField = NULL;
+    jfieldID dhcpField = NULL;
+    jfieldID bridgeField = NULL;
+    jfieldID broadcastEnabledField = NULL;
+    jfieldID portErrorField = NULL;
+    jfieldID enabledField = NULL;
+    jfieldID netconfRevisionField = NULL;
+    jfieldID multicastSubscriptionsField = NULL;
+    jfieldID assignedAddressesField = NULL;
 
     if(vnetConfigClass == NULL)
     {
@@ -937,26 +836,20 @@ jobject newNetworkConfig(JNIEnv *env, const ZT1_VirtualNetworkConfig &vnetConfig
 jobject newVersion(JNIEnv *env, int major, int minor, int rev, long featureFlags)
 {
    // create a com.zerotierone.sdk.Version object
-    static jclass versionClass = NULL;
-    static jmethodID versionConstructor = NULL;
+    jclass versionClass = NULL;
+    jmethodID versionConstructor = NULL;
 
+    versionClass = env->FindClass("com/zerotierone/sdk/Version");
     if(versionClass == NULL)
     {
-        versionClass = env->FindClass("com/zerotierone/sdk/Version");
-        if(versionClass == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    versionConstructor = env->GetMethodID(
+        versionClass, "<init>", "()V");
     if(versionConstructor == NULL)
     {
-        versionConstructor = env->GetMethodID(
-            versionClass, "<init>", "()V");
-        if(versionConstructor == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
     jobject versionObj = env->NewObject(versionClass, versionConstructor);
@@ -966,45 +859,33 @@ jobject newVersion(JNIEnv *env, int major, int minor, int rev, long featureFlags
     }
 
     // copy data to Version object
-    static jfieldID majorField = NULL;
-    static jfieldID minorField = NULL;
-    static jfieldID revisionField = NULL;
-    static jfieldID featureFlagsField = NULL;
+    jfieldID majorField = NULL;
+    jfieldID minorField = NULL;
+    jfieldID revisionField = NULL;
+    jfieldID featureFlagsField = NULL;
 
-    if(majorField == NULL)
+    majorField = env->GetFieldID(versionClass, "major", "I");
+    if(majorField = NULL)
     {
-        majorField = env->GetFieldID(versionClass, "major", "I");
-        if(majorField = NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    minorField = env->GetFieldID(versionClass, "minor", "I");
     if(minorField == NULL)
     {
-        minorField = env->GetFieldID(versionClass, "minor", "I");
-        if(minorField == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    revisionField = env->GetFieldID(versionClass, "revision", "I");
     if(revisionField == NULL)
     {
-        revisionField = env->GetFieldID(versionClass, "revision", "I");
-        if(revisionField == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    featureFlagsField = env->GetFieldID(versionClass, "featureFlags", "J");
     if(featureFlagsField == NULL)
     {
-        featureFlagsField = env->GetFieldID(versionClass, "featureFlags", "J");
-        if(featureFlagsField == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
     env->SetIntField(versionObj, majorField, (jint)major);

java/jni/com_zerotierone_sdk_Node.cpp

@@ -43,64 +43,28 @@ namespace {
     struct JniRef
     {
         JniRef()
-            : env(NULL)
+            : jvm(NULL)
             , node(NULL)
             , dataStoreGetListener(NULL)
-            , dataStoreGetClass(NULL)
-            , dataStoreGetCallbackMethod(NULL)
             , dataStorePutListener(NULL)
-            , dataStorePutClass(NULL)
-            , dataStorePutCallbackMethod(NULL)
-            , deleteMethod(NULL)
             , packetSender(NULL)
-            , packetSenderClass(NULL)
-            , packetSenderCallbackMethod(NULL)
             , eventListener(NULL)
-            , eventListenerClass(NULL)
-            , onEventMethod(NULL)
-            , onOutOfDateMethod(NULL)
-            , onNetworkErrorMethod(NULL)
-            , onTraceMethod(NULL)
             , frameListener(NULL)
-            , frameListenerClass(NULL)
-            , frameListenerCallbackMethod(NULL)
             , configListener(NULL)
-            , configListenerClass(NULL)
-            , configListenerCallbackMethod(NULL)
         {}
+
         uint64_t id;
 
-        JNIEnv *env;
+        JavaVM *jvm;
 
         ZT1_Node *node;
 
         jobject dataStoreGetListener;
-        jclass dataStoreGetClass;
-        jmethodID dataStoreGetCallbackMethod;
-
         jobject dataStorePutListener;
-        jclass dataStorePutClass;
-        jmethodID dataStorePutCallbackMethod;
-        jmethodID deleteMethod;
-
         jobject packetSender;
-        jclass packetSenderClass;
-        jmethodID packetSenderCallbackMethod;
-        
         jobject eventListener;
-        jclass eventListenerClass;
-        jmethodID onEventMethod;
-        jmethodID onOutOfDateMethod;
-        jmethodID onNetworkErrorMethod;
-        jmethodID onTraceMethod;
-
         jobject frameListener;
-        jclass frameListenerClass;
-        jmethodID frameListenerCallbackMethod;
-
         jobject configListener;
-        jclass configListenerClass;
-        jmethodID configListenerCallbackMethod;
     };
 
 
@@ -112,30 +76,23 @@ namespace {
         const ZT1_VirtualNetworkConfig *config)
     {
         JniRef *ref = (JniRef*)userData;
-        assert(ref->node == node);
+        JNIEnv *env = NULL;
+        ref->jvm->GetEnv((void**)&env, JNI_VERSION_1_6);
 
-        JNIEnv *env = ref->env;
-
-        if(ref->configListenerClass == NULL)
+        jclass configListenerClass = env->GetObjectClass(ref->configListener);
+        if(configListenerClass == NULL)
         {
-            ref->configListenerClass = env->GetObjectClass(ref->configListener);
-            if(ref->configListenerClass == NULL)
-            {
-                LOGE("Couldn't find class for VirtualNetworkConfigListener instance");
-                return -1;
-            }
+            LOGE("Couldn't find class for VirtualNetworkConfigListener instance");
+            return -1;
         }
 
-        if(ref->configListenerCallbackMethod == NULL)
+        jmethodID configListenerCallbackMethod = env->GetMethodID(configListenerClass,
+            "onNetworkConfigurationUpdated",
+            "(JLcom/zerotierone/sdk/VirtualNetworkConfigOperation;Lcom/zerotierone/sdk/VirtualNetworkConfig;)I");
+        if(configListenerCallbackMethod == NULL)
         {
-            ref->configListenerCallbackMethod = env->GetMethodID(ref->configListenerClass,
-                "onNetworkConfigurationUpdated",
-                "(JLcom/zerotierone/sdk/VirtualNetworkConfigOperation;Lcom/zerotierone/sdk/VirtualNetworkConfig;)I");
-            if(ref->configListenerCallbackMethod == NULL)
-            {
-                LOGE("Couldn't find onVirtualNetworkFrame() method");
-                return -2;
-            }
+            LOGE("Couldn't find onVirtualNetworkFrame() method");
+            return -2;
         }
 
         jobject operationObject = createVirtualNetworkConfigOperation(env, operation);
@@ -154,7 +111,7 @@ namespace {
 
         return env->CallIntMethod(
             ref->configListener, 
-            ref->configListenerCallbackMethod, 
+            configListenerCallbackMethod, 
             (jlong)nwid, operationObject, networkConfigObject);
     }
 
@@ -169,35 +126,30 @@ namespace {
     {
         JniRef *ref = (JniRef*)userData;
         assert(ref->node == node);
+        JNIEnv *env = NULL;
+        ref->jvm->GetEnv((void**)&env, JNI_VERSION_1_6);
 
-        JNIEnv *env = ref->env;
 
-        if(ref->frameListenerClass == NULL)
+        jclass frameListenerClass = env->GetObjectClass(ref->frameListener);
+        if(frameListenerClass == NULL)
         {
-            ref->frameListenerClass = env->GetObjectClass(ref->frameListener);
-            if(ref->frameListenerClass == NULL)
-            {
-                LOGE("Couldn't find class for VirtualNetworkFrameListener instance");
-                return;
-            }
+            LOGE("Couldn't find class for VirtualNetworkFrameListener instance");
+            return;
         }
 
-        if(ref->frameListenerCallbackMethod == NULL)
+        jmethodID frameListenerCallbackMethod = env->GetMethodID(
+            frameListenerClass,
+            "onVirtualNetworkFrame", "(JJJJJ[B)V");
+        if(frameListenerCallbackMethod == NULL)
         {
-            ref->frameListenerCallbackMethod = env->GetMethodID(
-                ref->frameListenerClass,
-                "onVirtualNetworkFrame", "(JJJJJ[B)V");
-            if(ref->frameListenerCallbackMethod == NULL)
-            {
-                LOGE("Couldn't find onVirtualNetworkFrame() method");
-                return;
-            }
+            LOGE("Couldn't find onVirtualNetworkFrame() method");
+            return;
         }
 
         jbyteArray dataArray = env->NewByteArray(frameLength);
         env->SetByteArrayRegion(dataArray, 0, frameLength, (jbyte*)frameData);
 
-        env->CallVoidMethod(ref->frameListener, ref->frameListenerCallbackMethod, nwid, sourceMac, destMac, etherType, vlanid, dataArray);
+        env->CallVoidMethod(ref->frameListener, frameListenerCallbackMethod, nwid, sourceMac, destMac, etherType, vlanid, dataArray);
     }
 
 
@@ -205,64 +157,50 @@ namespace {
     {
         JniRef *ref = (JniRef*)userData;
         assert(ref->node == node);
+        JNIEnv *env = NULL;
+        ref->jvm->GetEnv((void**)&env, JNI_VERSION_1_6);
 
-        JNIEnv *env = ref->env;
 
-        if(ref->eventListenerClass == NULL)
+        jclass eventListenerClass = env->GetObjectClass(ref->eventListener);
+        if(eventListenerClass == NULL)
         {
-            ref->eventListenerClass = env->GetObjectClass(ref->eventListener);
-            if(ref->eventListenerClass == NULL)
-            {
-                LOGE("Couldn't class for EventListener instance");
-                return;
-            }
+            LOGE("Couldn't class for EventListener instance");
+            return;
         }
 
-        if(ref->onEventMethod == NULL)
+        jmethodID onEventMethod = env->GetMethodID(eventListenerClass,
+            "onEvent", "(Lcom/zerotierone/sdk/Event;)V");
+        if(onEventMethod == NULL)
         {
-            ref->onEventMethod = env->GetMethodID(ref->eventListenerClass,
-                "onEvent", "(Lcom/zerotierone/sdk/Event;)V");
-            if(ref->onEventMethod == NULL)
-            {
-                LOGE("Couldn't find onEvent method");
-                return;
-            }
+            LOGE("Couldn't find onEvent method");
+            return;
         }
 
 
-        if(ref->onOutOfDateMethod == NULL)
+        jmethodID onOutOfDateMethod = env->GetMethodID(eventListenerClass,
+            "onOutOfDate", "(Lcom/zerotierone/sdk/Version;)V");
+        if(onOutOfDateMethod == NULL)
         {
-            ref->onOutOfDateMethod = env->GetMethodID(ref->eventListenerClass,
-                "onOutOfDate", "(Lcom/zerotierone/sdk/Version;)V");
-            if(ref->onOutOfDateMethod == NULL)
-            {
-                LOGE("Couldn't find onOutOfDate method");
-                return;
-            }
+            LOGE("Couldn't find onOutOfDate method");
+            return;
         }
 
 
-        if(ref->onOutOfDateMethod == NULL)
+        jmethodID onNetworkErrorMethod = env->GetMethodID(eventListenerClass,
+            "onNetworkError", "(Lcom/zerotierone/sdk/Event;Ljava/net/InetSocketAddress;)V");
+        if(onNetworkErrorMethod == NULL)
         {
-            ref->onNetworkErrorMethod = env->GetMethodID(ref->eventListenerClass,
-                "onNetworkError", "(Lcom/zerotierone/sdk/Event;Ljava/net/InetSocketAddress;)V");
-            if(ref->onNetworkErrorMethod == NULL)
-            {
-                LOGE("Couldn't find onNetworkError method");
-                return;
-            }
+            LOGE("Couldn't find onNetworkError method");
+            return;
         }
 
 
-        if(ref->onTraceMethod == NULL)
+        jmethodID onTraceMethod = env->GetMethodID(eventListenerClass,
+            "onTrace", "(Ljava/lang/String;)V");
+        if(onTraceMethod == NULL)
         {
-            ref->onTraceMethod = env->GetMethodID(ref->eventListenerClass,
-                "onTrace", "(Ljava/lang/String;)V");
-            if(ref->onTraceMethod == NULL)
-            {
-                LOGE("Couldn't find onTrace method");
-                return;
-            }
+            LOGE("Couldn't find onTrace method");
+            return;
         }
 
         jobject eventObject = createEvent(env, event);
@@ -280,7 +218,7 @@ namespace {
         case ZT1_EVENT_FATAL_ERROR_IDENTITY_COLLISION:
         {
             // call onEvent()
-            env->CallVoidMethod(ref->eventListener, ref->onEventMethod, eventObject);
+            env->CallVoidMethod(ref->eventListener, onEventMethod, eventObject);
         }
         break;
         case ZT1_EVENT_SAW_MORE_RECENT_VERSION:
@@ -290,7 +228,7 @@ namespace {
             {
                 int *version = (int*)data;
                 jobject verisonObj = newVersion(env, version[0], version[1], version[2], 0);
-                env->CallVoidMethod(ref->eventListener, ref->onOutOfDateMethod, verisonObj);
+                env->CallVoidMethod(ref->eventListener, onOutOfDateMethod, verisonObj);
             }
         }
         break;
@@ -302,7 +240,7 @@ namespace {
             {
                 sockaddr_storage *addr = (sockaddr_storage*)data;
                 jobject addressObj = newInetSocketAddress(env, *addr);
-                env->CallVoidMethod(ref->eventListener, ref->onNetworkErrorMethod, addressObj);
+                env->CallVoidMethod(ref->eventListener, onNetworkErrorMethod, addressObj);
             }
         }
         case ZT1_EVENT_TRACE:
@@ -312,7 +250,7 @@ namespace {
             {
                 const char* message = (const char*)data;
                 jstring messageStr = env->NewStringUTF(message);
-                env->CallVoidMethod(ref->eventListener, ref->onTraceMethod);
+                env->CallVoidMethod(ref->eventListener, onTraceMethod);
             }
         }
         break;
@@ -327,29 +265,24 @@ namespace {
         unsigned long *out_objectSize)
     {
         JniRef *ref = (JniRef*)userData;
-        JNIEnv *env = ref->env;
+        JNIEnv *env = NULL;
+        ref->jvm->GetEnv((void**)&env, JNI_VERSION_1_6);
 
-        if(ref->dataStoreGetClass == NULL)
+        jclass dataStoreGetClass = env->GetObjectClass(ref->dataStoreGetListener);
+        if(dataStoreGetClass == NULL)
         {
-            ref->dataStoreGetClass = env->GetObjectClass(ref->dataStoreGetListener);
-            if(ref->dataStoreGetClass == NULL)
-            {
-                LOGE("Couldn't find class for DataStoreGetListener instance");
-                return -1;
-            }
+            LOGE("Couldn't find class for DataStoreGetListener instance");
+            return -1;
         }
 
-        if(ref->dataStoreGetCallbackMethod == NULL)
+        jmethodID dataStoreGetCallbackMethod = env->GetMethodID(
+            dataStoreGetClass,
+            "onDataStoreGet",
+            "(Ljava/lang/String;[BJ[J)J");
+        if(dataStoreGetCallbackMethod == NULL)
         {
-            ref->dataStoreGetCallbackMethod = env->GetMethodID(
-                ref->dataStoreGetClass,
-                "onDataStoreGet",
-                "(Ljava/lang/String;[BJ[J)J");
-            if(ref->dataStoreGetCallbackMethod == NULL)
-            {
-                LOGE("Couldn't find onDataStoreGet method");
-                return -2;
-            }
+            LOGE("Couldn't find onDataStoreGet method");
+            return -2;
         }
 
         jstring nameStr = env->NewStringUTF(objectName);
@@ -363,7 +296,7 @@ namespace {
         jlongArray objectSizeObj = env->NewLongArray(1);
 
         long retval = env->CallLongMethod(
-            ref->dataStoreGetListener, ref->dataStoreGetCallbackMethod, 
+            ref->dataStoreGetListener, dataStoreGetCallbackMethod, 
             nameStr, bufferObj, bufferIndex, objectSizeObj);
 
         env->GetByteArrayRegion(bufferObj, 0, bufferSize, (jbyte*)buffer);
@@ -381,40 +314,33 @@ namespace {
         int secure)
     {
         JniRef *ref = (JniRef*)userData;
-        JNIEnv *env = ref->env;
+        JNIEnv *env = NULL;
+        ref->jvm->GetEnv((void**)&env, JNI_VERSION_1_6);
 
-        if(ref->dataStorePutClass == NULL)
+
+        jclass dataStorePutClass = env->GetObjectClass(ref->dataStorePutListener);
+        if(dataStorePutClass == NULL)
         {
-            ref->dataStorePutClass = env->GetObjectClass(ref->dataStorePutListener);
-            if(ref->dataStorePutClass == NULL)
-            {
-                LOGE("Couldn't find class for DataStorePutListener instance");
-                return -1;
-            }
+            LOGE("Couldn't find class for DataStorePutListener instance");
+            return -1;
         }
 
-        if(ref->dataStorePutCallbackMethod == NULL)
+        jmethodID dataStorePutCallbackMethod = env->GetMethodID(
+            dataStorePutClass,
+            "onDataStorePut",
+            "(Ljava/lang/String;[BZ)I");
+        if(dataStorePutCallbackMethod == NULL)
         {
-            ref->dataStorePutCallbackMethod = env->GetMethodID(
-                ref->dataStorePutClass,
-                "onDataStorePut",
-                "(Ljava/lang/String;[BZ)I");
-            if(ref->dataStorePutCallbackMethod == NULL)
-            {
-                LOGE("Couldn't find onDataStorePut method");
-                return -2;
-            }
+            LOGE("Couldn't find onDataStorePut method");
+            return -2;
         }
 
-        if(ref->deleteMethod == NULL)
+        jmethodID deleteMethod = env->GetMethodID(dataStorePutClass,
+            "onDelete", "(Ljava/lang/String;)I");
+        if(deleteMethod == NULL)
         {
-            ref->deleteMethod = env->GetMethodID(ref->dataStorePutClass,
-                "onDelete", "(Ljava/lang/String;)I");
-            if(ref->deleteMethod == NULL)
-            {
-                LOGE("Couldn't find onDelete method");
-                return -3;
-            }
+            LOGE("Couldn't find onDelete method");
+            return -3;
         }
 
         jstring nameStr = env->NewStringUTF(objectName);
@@ -423,7 +349,7 @@ namespace {
         {
             // delete operation
             return env->CallIntMethod(
-                ref->dataStorePutListener, ref->deleteMethod, nameStr);
+                ref->dataStorePutListener, deleteMethod, nameStr);
         }
         else
         {
@@ -434,7 +360,7 @@ namespace {
 
 
             return env->CallIntMethod(ref->dataStorePutListener,
-                ref->dataStorePutCallbackMethod,
+                dataStorePutCallbackMethod,
                 nameStr, bufferObj, secure);
         }
     }
@@ -448,33 +374,29 @@ namespace {
         JniRef *ref = (JniRef*)userData;
         assert(ref->node == node);
 
-        JNIEnv *env = ref->env;
+        JNIEnv *env = NULL;
+        ref->jvm->GetEnv((void**)&env, JNI_VERSION_1_6);
 
-        if(ref->packetSenderClass == NULL)
+
+        jclass packetSenderClass = env->GetObjectClass(ref->packetSender);
+        if(packetSenderClass == NULL)
         {
-            ref->packetSenderClass = env->GetObjectClass(ref->packetSender);
-            if(ref->packetSenderClass == NULL)
-            {
-                LOGE("Couldn't find class for PacketSender instance");
-                return -1;
-            }
+            LOGE("Couldn't find class for PacketSender instance");
+            return -1;
         }
 
-        if(ref->packetSenderCallbackMethod == NULL)
+        jmethodID packetSenderCallbackMethod = env->GetMethodID(packetSenderClass,
+            "onSendPacketRequested", "(Ljava/net/InetSocketAddress;I[B)I");
+        if(packetSenderCallbackMethod == NULL)
         {
-            ref->packetSenderCallbackMethod = env->GetMethodID(ref->packetSenderClass,
-                "onSendPacketRequested", "(Ljava/net/InetSocketAddress;I[B)I");
-            if(ref->packetSenderCallbackMethod == NULL)
-            {
-                LOGE("Couldn't find onSendPacketRequested method");
-                return -2;
-            }
+            LOGE("Couldn't find onSendPacketRequested method");
+            return -2;
         }
         
         jobject addressObj = newInetSocketAddress(env, *address);
         jbyteArray bufferObj = env->NewByteArray(bufferSize);
         env->SetByteArrayRegion(bufferObj, 0, bufferSize, (jbyte*)buffer);
-        return env->CallIntMethod(ref->packetSender, ref->packetSenderCallbackMethod, addressObj, linkDesparation, bufferObj);
+        return env->CallIntMethod(ref->packetSender, packetSenderCallbackMethod, addressObj, linkDesparation, bufferObj);
     }
 
     typedef std::map<uint64_t, JniRef*> NodeMap;
@@ -506,7 +428,7 @@ JNIEXPORT jobject JNICALL Java_com_zerotierone_sdk_Node_node_1init(
     ZT1_Node *node;
     JniRef *ref = new JniRef;
     ref->id = (uint64_t)now;
-    ref->env = env;
+    env->GetJavaVM(&ref->jvm);
 
     jclass cls = env->GetObjectClass(obj);
     jfieldID fid = env->GetFieldID(
@@ -1019,28 +941,21 @@ JNIEXPORT jobject JNICALL Java_com_zerotierone_sdk_Node_status
         return 0;
     }
 
-    // static so we only have to look these up once
-    static jclass nodeStatusClass = NULL;
-    static jmethodID nodeStatusConstructor = NULL;
+    jclass nodeStatusClass = NULL;
+    jmethodID nodeStatusConstructor = NULL;
 
     // create a com.zerotierone.sdk.NodeStatus object
+    nodeStatusClass = env->FindClass("com/zerotierone/sdk/NodeStatus");
     if(nodeStatusClass == NULL)
     {
-        nodeStatusClass = env->FindClass("com/zerotierone/sdk/NodeStatus");
-        if(nodeStatusClass == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
     
+    nodeStatusConstructor = env->GetMethodID(
+        nodeStatusClass, "<init>", "()V");
     if(nodeStatusConstructor == NULL)
     {
-        nodeStatusConstructor = env->GetMethodID(
-            nodeStatusClass, "<init>", "()V");
-        if(nodeStatusConstructor == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
     jobject nodeStatusObj = env->NewObject(nodeStatusClass, nodeStatusConstructor);
@@ -1052,45 +967,33 @@ JNIEXPORT jobject JNICALL Java_com_zerotierone_sdk_Node_status
     ZT1_NodeStatus nodeStatus;
     ZT1_Node_status(node, &nodeStatus);
 
-    static jfieldID addressField = NULL;
-    static jfieldID publicIdentityField = NULL;
-    static jfieldID secretIdentityField = NULL;
-    static jfieldID onlineField = NULL;
+    jfieldID addressField = NULL;
+    jfieldID publicIdentityField = NULL;
+    jfieldID secretIdentityField = NULL;
+    jfieldID onlineField = NULL;
 
+    addressField = env->GetFieldID(nodeStatusClass, "address", "J");
     if(addressField == NULL)
     {
-        addressField = env->GetFieldID(nodeStatusClass, "address", "J");
-        if(addressField == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    publicIdentityField = env->GetFieldID(nodeStatusClass, "publicIdentity", "Ljava/lang/String;");
     if(publicIdentityField == NULL)
     {
-        publicIdentityField = env->GetFieldID(nodeStatusClass, "publicIdentity", "Ljava/lang/String;");
-        if(publicIdentityField == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    secretIdentityField = env->GetFieldID(nodeStatusClass, "secretIdentity", "Ljava/lang/String;");
     if(secretIdentityField == NULL)
     {
-        secretIdentityField = env->GetFieldID(nodeStatusClass, "secretIdentity", "Ljava/lang/String;");
-        if(secretIdentityField == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
+    onlineField = env->GetFieldID(nodeStatusClass, "online", "Z");
     if(onlineField == NULL)
     {
-        onlineField = env->GetFieldID(nodeStatusClass, "online", "Z");
-        if(onlineField == NULL)
-        {
-            return NULL;
-        }
+        return NULL;
     }
 
     env->SetLongField(nodeStatusObj, addressField, nodeStatus.address);