[HTC Wildfire S] izi501:
The Android source code for JNI shows that this error is here because

(*env)->FindClass(env, className)

returned nothing. I didn't look into a C++ code for a long time, but that means that the FindClass function failed. In Android JNI documentation, the cause of such an error is explained : http://developer.android.com/training/articles/perf-jni.html#faq_FindClass.

---------- Post added at 08:49 PM ---------- Previous post was at 08:40 PM ----------

The other solution would be to decompile every framework .jar and .apk and to find exactly which files refer to "com/android/server/NetworkManagementSocketTagger".

EDIT : That's what I'm doing right now ;)

---------- Post added at 09:27 PM ---------- Previous post was at 08:49 PM ----------

Okay, so I decompiled every framework apk and looked for the string "com/android/server/NetworkManagementSocketTagger". Here are the results :

framework.jar.out/smali/com/android/internal/os/RuntimeInit.smali: invoke-static {}, Lcom/android/server/NetworkManagementSocketTagger;->install()V
framework.jar.out/smali/com/android/internal/net/NetworkStatsFactory.smali: invoke-static {v12}, Lcom/android/server/NetworkManagementSocketTagger;->kernelToTag(Ljava/lang/String;)I
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali:.class public final Lcom/android/server/NetworkManagementSocketTagger;
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: Lcom/android/server/NetworkManagementSocketTagger$SocketTags;
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: "Lcom/android/server/NetworkManagementSocketTagger$SocketTags;",
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: new-instance v0, Lcom/android/server/NetworkManagementSocketTagger$1;
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: invoke-direct {v0}, Lcom/android/server/NetworkManagementSocketTagger$1;-><init>()V
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: sput-object v0, Lcom/android/server/NetworkManagementSocketTagger;->threadSocketTags:Ljava/lang/ThreadLocal;
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: sget-object v0, Lcom/android/server/NetworkManagementSocketTagger;->threadSocketTags:Ljava/lang/ThreadLocal;
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: check-cast v0, Lcom/android/server/NetworkManagementSocketTagger$SocketTags;
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: iget v0, v0, Lcom/android/server/NetworkManagementSocketTagger$SocketTags;->statsTag:I
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: new-instance v0, Lcom/android/server/NetworkManagementSocketTagger;
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: invoke-direct {v0}, Lcom/android/server/NetworkManagementSocketTagger;-><init>()V
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: invoke-static {v1, p0}, Lcom/android/server/NetworkManagementSocketTagger;->native_deleteTagData(II)I
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: invoke-static {p1, p0}, Lcom/android/server/NetworkManagementSocketTagger;->native_setCounterSet(II)I
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: sget-object v0, Lcom/android/server/NetworkManagementSocketTagger;->threadSocketTags:Ljava/lang/ThreadLocal;
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: check-cast v0, Lcom/android/server/NetworkManagementSocketTagger$SocketTags;
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: iput p0, v0, Lcom/android/server/NetworkManagementSocketTagger$SocketTags;->statsTag:I
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: sget-object v0, Lcom/android/server/NetworkManagementSocketTagger;->threadSocketTags:Ljava/lang/ThreadLocal;
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: check-cast v0, Lcom/android/server/NetworkManagementSocketTagger$SocketTags;
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: iput p0, v0, Lcom/android/server/NetworkManagementSocketTagger$SocketTags;->statsUid:I
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: invoke-static {p1, p2, p3}, Lcom/android/server/NetworkManagementSocketTagger;->native_tagSocketFd(Ljava/io/FileDescriptor;II)I
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: sget-object v2, Lcom/android/server/NetworkManagementSocketTagger;->threadSocketTags:Ljava/lang/ThreadLocal;
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: check-cast v1, Lcom/android/server/NetworkManagementSocketTagger$SocketTags;
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: .local v1, options:Lcom/android/server/NetworkManagementSocketTagger$SocketTags;
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: iget v2, v1, Lcom/android/server/NetworkManagementSocketTagger$SocketTags;->statsTag:I
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: iget v2, v1, Lcom/android/server/NetworkManagementSocketTagger$SocketTags;->statsUid:I
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: invoke-static {p1}, Lcom/android/server/NetworkManagementSocketTagger;->native_untagSocketFd(Ljava/io/FileDescriptor;)I
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: sget-object v1, Lcom/android/server/NetworkManagementSocketTagger;->threadSocketTags:Ljava/lang/ThreadLocal;
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: check-cast v0, Lcom/android/server/NetworkManagementSocketTagger$SocketTags;
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: .local v0, options:Lcom/android/server/NetworkManagementSocketTagger$SocketTags;
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: iget v1, v0, Lcom/android/server/NetworkManagementSocketTagger$SocketTags;->statsTag:I
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: iget v2, v0, Lcom/android/server/NetworkManagementSocketTagger$SocketTags;->statsUid:I
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: invoke-direct {p0, p1, v1, v2}, Lcom/android/server/NetworkManagementSocketTagger;->tagSocketFd(Ljava/io/FileDescriptor;II)V
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger.smali: invoke-direct {p0, p1}, Lcom/android/server/NetworkManagementSocketTagger;->unTagSocketFd(Ljava/io/FileDescriptor;)V
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger$1.smali:.class final Lcom/android/server/NetworkManagementSocketTagger$1;
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger$1.smali: value = Lcom/android/server/NetworkManagementSocketTagger;
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger$1.smali: "Lcom/android/server/NetworkManagementSocketTagger$SocketTags;",
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger$1.smali:.method protected initialValue()Lcom/android/server/NetworkManagementSocketTagger$SocketTags;
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger$1.smali: new-instance v0, Lcom/android/server/NetworkManagementSocketTagger$SocketTags;
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger$1.smali: invoke-direct {v0}, Lcom/android/server/NetworkManagementSocketTagger$SocketTags;-><init>()V
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger$1.smali: invoke-virtual {p0}, Lcom/android/server/NetworkManagementSocketTagger$1;->initialValue()Lcom/android/server/NetworkManagementSocketTagger$SocketTags;
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger$SocketTags.smali:.class public Lcom/android/server/NetworkManagementSocketTagger$SocketTags;
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger$SocketTags.smali: value = Lcom/android/server/NetworkManagementSocketTagger;
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger$SocketTags.smali: iput v0, p0, Lcom/android/server/NetworkManagementSocketTagger$SocketTags;->statsTag:I
framework.jar.out/smali/com/android/server/NetworkManagementSocketTagger$SocketTags.smali: iput v0, p0, Lcom/android/server/NetworkManagementSocketTagger$SocketTags;->statsUid:I
framework.jar.out/smali/android/net/TrafficStats.smali: invoke-static {v0}, Lcom/android/server/NetworkManagementSocketTagger;->setThreadSocketStatsTag(I)V
framework.jar.out/smali/android/net/TrafficStats.smali: invoke-static {v0}, Lcom/android/server/NetworkManagementSocketTagger;->setThreadSocketStatsUid(I)V
framework.jar.out/smali/android/net/TrafficStats.smali: invoke-static {}, Lcom/android/server/NetworkManagementSocketTagger;->getThreadSocketStatsTag()I
framework.jar.out/smali/android/net/TrafficStats.smali: invoke-static {p0}, Lcom/android/server/NetworkManagementSocketTagger;->setThreadSocketStatsTag(I)V
framework.jar.out/smali/android/net/TrafficStats.smali: invoke-static {p0}, Lcom/android/server/NetworkManagementSocketTagger;->setThreadSocketStatsUid(I)V
services.jar.out/smali/com/android/server/net/NetworkStatsService.smali: invoke-static {p1}, Lcom/android/server/NetworkManagementSocketTagger;->resetKernelUidStats(I)V
services.jar.out/smali/com/android/server/net/NetworkStatsService.smali: invoke-static {p1, v1}, Lcom/android/server/NetworkManagementSocketTagger;->setKernelCounterSet(II)V

But there is nothing really interesting in that, I'm afraid.